Phosphonooxymethyl ethers of taxane derivatives

ABSTRACT

The present invention concerns antitumor compounds. More particularly, the invention provides novel taxane derivatives, pharmaceutical compositions thereof, and their use as antitumor agents.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. Ser. No. 08/245,119 filed May17, 1994, now abandoned which is a continuation-in-part of U.S. Ser. No.08/154,840 filed Nov. 24, 1993, now abandoned which is acontinuation-in-part of U.S. Ser. No. 08/108,015 filed Aug. 17, 1993,now abandoned, which in turn is a continuation-in-part of U.S. Ser. No.07/996,455 filed Dec. 24, 1992, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention concerns antitumor compounds. More particularly,the invention provides novel taxane derivatives, pharmaceuticalcompositions thereof, and their use as antitumor agents.

2. Background Art

Taxol® (paclitaxel) is a natural product extracted from the bark ofPacific yew trees, Taxus brevifolia. It has been shown to have excellentantitumor activity in in vivo animal models, and recent studies haveelucidated its unique mode of action, which involves abnormalpolymerization of tubulin and disruption of mitosis. It was recentlyapproved for the treatment of ovarian cancer; and studies involvingbreast, colon, and lung cancers have shown promising results. Theresults of paclitaxel clinical studies are reviewed in Rowinsky andDonehower, "The Clinical Pharmacology and Use of Antimicrotubule Agentsin Cancer Chemotherapeutics" Pharmac. Ther., 52:35-84, 1991.

Recently, a semi-synthetic analog of paclitaxel named Taxotere® has alsobeen found to have good antitumor activity in animal models. Taxotere®is also currently undergoing clinical trials in Europe and the UnitedStates. The structures of paclitaxel and Taxotere® are shown below; theconventional numbering system of the paclitaxel molecule is provided.##STR1## Taxol®: R=Ph; R'=acetyl Taxotere®: R=t-butoxy; R'=hydrogen

One drawback of paclitaxel is its very limited water solubilityrequiring it to be formulated in nonaqueous pharmaceutical vehicles. Onecommonly used carrier is Cremophor EL which may itself have undesirableside effects in man. Accordingly, a number of research teams haveprepared water-soluble derivatives of paclitaxel which are disclosed inthe following references:

(a) Haugwitz et al, U.S. Pat. No. 4,942,184;

(b) Kingston et al, U.S. Pat. No. 5,059,699;

(c) Stella et al, U.S. Pat. No. 4,960,790;

(d) European Patent Application 0,558,959 A1 published Sep. 8, 1993;

(e) Vyas et al, Bioorganic & Medicinal Chemistry Letters, 1993,3:1357-1360; and

(f) Nicolaou et al, Nature, 1993, 364:464-466

Compounds of the present invention are phosphonooxymethyl ethers oftaxane derivatives and pharmaceutically acceptable salts thereof. Thewater solubility of the salts facilitates preparation of pharmaceuticalformulations.

SUMMARY OF THE INVENTION

The present invention relates to taxane derivatives having the formula(A):

    T-[OCH.sub.2 (OCH.sub.2).sub.m OP(O)(OH).sub.2 ].sub.n     (A)

wherein T is a taxane moiety bearing on the C13 carbon atom asubstituted 3-amino-2-hydroxypropanoyloxy group; n is 1, 2 or 3; m is 0or an integer from 1 to 6 inclusive; or a pharmaceutically acceptablesalt thereof.

Another aspect of the present invention provides taxane derivativeshaving the formula (B):

    T'-[OCH.sub.2 (OCH.sub.2).sub.m SCH.sub.3 ].sub.n          (B)

wherein T' is T in which non-reacting hydroxy groups have been blocked,m and n are as defined under formula (A).

Yet another aspect of the present invention provides intermediateshaving the formula (C):

    T'-[OCH.sub.2 (OCH.sub.2).sub.m OP(O)(OR.sup.y).sub.2 ].sub.n (C)

wherein T', m and n are as defined under formula (A), and R^(y) is aphosphono protecting group.

Another aspect of the present invention provides compounds of theformula (D):

    13-OH-txn-[OCH.sub.2 (OCH.sub.2).sub.m SCH.sub.3 ].sub.n   (D)

wherein m and n are as defined above; and txn is a taxane moiety; or aC13 metal alkoxide thereof.

Another aspect of the present invention provides a method for inhibitingtumor in a mammalian host which comprises administering to saidmammalian host an antitumor effective amount of a compound of formula(A).

Further aspect of the present invention provides a method for inhibitingtumor in a mammalian host which comprises administering to saidmammalian host an antitumor effective amount of a compound of theformula (B'): ##STR2## wherein R^(1b') is hydroxy, --OC(O)R^(x) or--OC(O)OR^(x) ; R^(3b') is hydrogen, hydroxy, --OC(O)OR^(x), C₁₋₆alkyloxy or --OC(O)R^(x) ; one of R^(6b') or R^(7b') is hydrogen and theother is hydroxy or C₁₋₆ alkanoyloxy; or R^(6b') and R^(7b') togetherform an oxo group; R⁴ and R⁵ are independently C₁₋₆ alkyl, C₂₋₆ alkenyl,C₂₋₆ alkynyl, or -Z-R⁶ ; Z is a direct bond, C₁₋₆ alkyl or C₂₋₆ alkenyl;R⁶ is aryl, substituted aryl, C₃₋₆ cycloalkyl or heteroaryl; p is 0 or1; R^(x) is C₁₋₆ alkyl optionally, substituted with one to six same ordifferent halogen atoms, C₃₋₆ cycloalkyl, C₂₋₆ alkenyl or hydroxy; orR^(x) is a radical of the formula ##STR3## wherein D is a bond or C₁₋₆alkyl; and R^(a), R^(b) and R^(c) are independently hydrogen, amino,C₁₋₆ alkylamino, di-C₁₋₆ alkylamino, halogen, C₁₋₆ alkyl, or C₁₋₆alkoxy.

Thus, another aspect of the present invention provides a pharmaceuticalcomposition which comprises an antitumor effective amount of a compoundof formula (B') or (A) and a pharmaceutically acceptable carrier.

DETAILED DESCRIPTION OF THE INVENTION

In the application, unless otherwise specified explicitly or in context,the following definitions apply. "Alkyl" means a straight or branchedsaturated carbon chain having from one to six carbon atoms; examplesinclude methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl,isobutyl, t-butyl, n-pentyl, sec-pentyl, isopentyl, and n-hexyl."Alkenyl" means a straight or branched carbon chain having at least onecarbon-carbon double bond, and having from two to six carbon atoms;examples include ethenyl, propenyl, isopropenyl, butenyl, isobutenyl,pentenyl, and hexenyl. "Alkynyl" means a straight or branched carbonchain having at least one carbon-carbon triple bond, and from two to sixcarbon atoms; examples include ethynyl, propynyl, butynyl, and hexynyl.

"Aryl" means aromatic hydrocarbon having from six to ten carbon atoms;examples include phenyl and naphthyl. "Substituted aryl" means arylsubstituted with at least one group selected from C₁₋₆ alkanoyloxy,hydroxy, halogen, C₁₋₆ alkyl, trifluoromethyl, C₁₋₆ alkoxy, aryl, C₂₋₆alkenyl, C₁₋₆ alkanoyl, nitro, amino, and amido. "Halogen" meansfluorine, chlorine, bromine, and iodine.

"Phosphono-" means the group --P(O)(OH)₂ and "phosphonooxymethoxy" or"phosphonooxymethyl ether" means generically the group --OCH₂ (OCH₂)_(m)OP(O)(OH)₂. "(Methylthio)thiocarbonyl" means the group --C(S)SCH₃."Methylthiomethyl" (also abbreviated as MTM) generically refers to thegroup --CH₂ SCH₃.

"Taxane moiety" (also abbreviated as txn) denotes moieties containingthe twenty carbon taxane core framework represented by the structuralformula shown below with the absolute configuration. ##STR4## Thenumbering system shown above is one used in conventional taxanenomenclature, and is followed throughout the application. For example,the notation C1 refers to the carbon atom labelled as "1"; C5-C20oxetane refers to an oxetane ring formed by the carbon atoms labelled as4, 5 and 20 with an oxygen atom; and C9 oxy refers to an oxygen atomattached to the carbon atom labelled as "9", said oxygen atom may be anoxo group, α- or β-hydroxy, or α- or β-acyloxy.

"Substituted 3-amino-2-hydroxypropanoyloxy" denotes a residuerepresented by the formula ##STR5## (X is a nonhydrogen group and X' ishydrogen or a non-hydrogen group.) The stereochemistry of this residueis the same as the paclitaxel sidechain. This group is sometimesreferred to in the application as the "C13 sidechain."

"Taxane derivative" (abbreviated as T) refers to a compound having ataxane moiety bearing a C13 sidechain.

"Heteroaryl" means a five- or six-membered aromatic ring containing atleast one and up to four non-carbon atoms selected from oxygen, sulfurand nitrogen. Examples of heteroaryl include thienyl, furyl, pyrrolyl,imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, oxazolyl, isoxazolyl,triazolyl, thiadiazolyl, oxadiazolyl, tetrazolyl, thiatriazolyl,oxatriazolyl, pyridyl, pyrimidyl, pyrazinyl, pyridazinyl, triazinyl,tetrazinyl, and like rings.

"Phosphono protecting groups" means moieties which can be employed toblock or protect the phosphono functional group; preferably suchprotecting groups are those that can be removed by methods that do notappreciably affect the rest of the molecule. Suitable phosphonooxyprotecting groups are well known to those skilled in the art and includefor example benzyl and allyl groups.

"Hydroxy protecting groups" include, but is not limited to, ethers suchas methyl, t-butyl, benzyl, p-methoxybenzyl, p-nitrobenzyl, allyl,trityl, methoxymethyl, methoxyethoxymethyl, ethoxyethyl,tetrahydropyranyl, tetrahydrothiopyranyl, and trialkylsilyl ethers suchas trimethylsilyl ether, triethylsilyl ether, and t-butyldimethylsilylether; esters such as benzoyl, acetyl, phenylacetyl, formyl, mono-, di-,and trihaloacetyl such as chloroacetyl, dichloroacetyl, trichloroacetyl,trifluoroacetyl; and carbonates such as methyl, ethyl,2,2,2-trichloroethyl, allyl, benzyl, and p-nitrophenyl.

Additional examples of hydroxy and phosphono protecting groups may befound in standard reference works such as Greene and Wuts, ProtectiveGroups in Organic Synthesis, 2d Ed., 1991, John Wiley & Sons, andMcOmie, Protective Groups in Organic Chemistry, 1975, Plenum Press.Methods for introducing and removing protecting groups are also found insuch textbooks.

"Pharmaceutically acceptable salt" means a metal or an amine salt of theacidic phosphono group in which the cation does not contributesignificantly to the toxicity or biological activity of the activecompound. Suitable metal salts include lithium, sodium, potassium,calcium, barium, magnesium, zinc, and aluminum salts. Preferred metalsalts are sodium and potassium salts. Suitable amine salts are forexample, ammonia, tromethamine (TRIS), triethylamine, procaine,benzathine, dibenzylamine, chloroprocaine, choline, diethanolamine,triethanolamine, ethylenediamine, glucamine, N-methylglucamine, lysine,arginine, ethanolamine, to name but a few. Preferred amine salts arelysine, arginine, triethanolamine, and N-methylglucamine salts. Evenmore preferred salt is N-methylglucamine or triethanolamine.

As used herein, the term --OCH₂ (OCH₂)_(m) OP(O)(OH)₂ is intended toemcompass both the free acid and its pharmaceutically acceptable salts,unless the context indicates specifically that the free acid is meant.

One aspect of the present invention provides taxane derivatives of theformula (A)

    T-[OCH.sub.2 (OCH.sub.2).sub.m OP(O)(OH).sub.2 ].sub.n     (A)

wherein T is a taxane moiety bearing on the C13 carbon atom asubstituted 3-amino-2-hydroxypropanoyloxy group; n is an 1, 2 or 3; m is0, or an integer from 1 to 6 inclusive, or a pharmaceutically acceptablesalt thereof.

Another aspect of the present invention provides taxane derivativeshaving the formula (B)

    T'-[OCH.sub.2 (OCH.sub.2).sub.m SCH.sub.3 ].sub.n          (B)

which are useful in making taxane derivatives of the formula (A).

In one embodiment the taxane moiety contains at least the followingfunctionalities: C1-hydroxy, C2-benzoyloxy, C4-acetyloxy, C5-C20oxetane, C9-oxy, and C11-C12 double bond.

In a preferred embodiment the taxane moiety is derived from a residuehaving the formula ##STR6## wherein R^(2e') is hydrogen and R^(2e) ishydrogen, hydroxy, --OC(O)R^(x), or --OC(O)OR^(x) ; R^(3e) is hydrogen,hydroxy, --OC(O)R^(x), --OC(O)OR^(x) or C₁₋₆ alkyloxy; one of R^(6e) orR^(7e) is hydrogen and the other is hydroxy or --OC(O)R^(x) ; or R^(6e)and R^(7e) together form an oxo group; R^(x) is as defined below.

In another embodiment, the C13 sidechain is derived from a residuehaving the formula ##STR7## wherein R^(1e) is hydrogen or --C(O)R^(x),--C(O)OR^(x) ; R⁴ and R⁵ are independently C₁₋₆ alkyl, C₂₋₆ alkenyl,C₂₋₆ alkynyl, or -Z-R⁶ ; Z is a direct bond, C₁₋₆ alkyl or C₂₋₆ alkenyl;R⁶ is aryl, substituted aryl, C₃₋₆ cycloalkyl, or heteroaryl; and R^(x)is C₁₋₆ alkyl optionally substituted with one to six same or differenthalogen atoms, C₃₋₆ cycloalkyl, C₂₋₆ alkenyl or hydroxy; or R^(x) is aradical of the formula ##STR8## wherein D is a bond or C₁₋₆ alkyl; andR^(a), R^(b) and R^(c) are independently hydrogen, amino, C₁₋₆alkylamino, di-C₁₋₆ alkylamino, halogen, C₁₋₆ alkyl, or C₁₋₆ alkoxy; pis 0 or 1.

In a preferred embodiment, R⁴ is C₁₋₆ alkyl and p is 1, or R⁴ is -Z-R⁶and p is 0. More preferably, R⁴ (O)_(p) is t-butoxy, phenyl,isopropyloxy, n-propyloxy, or n-butoxy.

In another preferred embodiment R⁵ is C₂₋₆ alkenyl or -Z-R⁶ and Z and R⁶are as previously defined. More preferably, R⁵ is phenyl, 2-furyl,2-thienyl, isobutenyl, 2-propenyl, or C₃₋₆ cycloalkyl.

In another embodiment, compound of formula (A) may be more specificallyrepresented by the formula (I) ##STR9## wherein R¹ is hydroxy, --OCH₂(OCH₂)_(m) OP(O)(OH)₂, --OC(O)R^(x) or --OC(O)OR^(x) ; R^(2') ishydrogen, and R² is hydrogen, hydroxy, --OCH₂ (OCH₂)_(m) OP(O)(OH)₂,--OC(O)R^(x) or --OC(O)OR^(x) ; R³ is hydrogen, hydroxy, C₁₋₆ alkyloxy,--OC(O)R^(x), --OCH₂ (OCH₂)_(m) OP(O)(OH)₂ or --OC(O)OR^(x) ; one of R⁶or R⁷ is hydrogen and the other is hydroxy, C₁₋₆ alkanoyloxy, or --OCH₂(OCH₂)_(m) OP(O)(OH)₂ ; or R⁶ and R⁷ together form an oxo group; withthe proviso that at least one of R¹, R², R³, R⁶ or R⁷ is --OCH₂(OCH₂)_(m) OP(O)(OH)₂ ; R⁴, R⁵, R^(x), m and p are as previouslydefined; or a pharmaceutically acceptable salt thereof.

In compounds of formula (I), examples of R^(x) include methyl,hydroxymethyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl,chloromethyl, 2,2,2-trichloroethyl, cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, ethenyl, 2-propenyl, phenyl, benzyl,bromophenyl, 4-aminophenyl, 4-methylaminophenyl, 4-methylphenyl,4-methoxyphenyl and the like. Examples of R⁴ and R⁵ include 2-propenyl,isobutenyl, 3-furanyl (3-furyl), 3-thienyl, phenyl, naphthyl,4-hydroxyphenyl, 4-methoxyphenyl, 4-fluorophenyl,4-trifluoromethylphenyl, methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, t-butyl, ethenyl, 2-propenyl, 2-propynyl, benzyl, phenethyl,phenylethenyl, 3,4-dimethoxyphenyl, 2-furanyl (2-furyl), 2-thienyl,2-(2-furanyl)ethenyl, 2-methylpropyl, cyclopropyl, cyclobutyl,cyclopentyl, cyclohexyl, cyclohexylmethyl, cyclohexylethyl and the like.

In one embodiment, the present invention provides a preferred group ofcompounds of formula (I) in which R⁵ is C₂₋₆ alkenyl or -Z-R⁶ and Z andR⁶ are as previously defined. More preferably, R⁵ is phenyl, 3-furyl,3-thienyl, 2-propenyl, isobutenyl, 2-furyl, 2-thienyl, or C₃₋₆cycloalkyl.

In another preferred embodiment R⁴ of compounds of formula (I) is C₁₋₆alkyl in which case p is 1; or R⁴ is -Z-R⁶ and Z and R⁶ are aspreviously defined, and in which case p is 0. More preferably R⁴(O)_(p) - is t-butoxy, phenyl, isopropyloxy, n-propyloxy, n-butoxy.

In another preferred embodiment, the present invention providescompounds of formula (I) in which R¹ is --OCH₂ (OCH₂)_(m) OP(O)(OH)₂. Ina more preferred embodiment, R² is hydroxy, --OCH₂ (OCH₂)_(m)OP(O)(OH)₂, --OC(O)OR^(x) or --OC(O)R^(x), and R^(x) is preferably C₁₋₆alkyl. In another more preferred embodiment, R³ is hydroxy or acetoxy.

In another preferred embodiment, the present invention provides compoundof formula (I) in which R² is --OCH₂ (OCH₂)_(m) OP(O)(OH)₂ ; R¹ ishydroxy, --OC(O)R^(x) or --OC(O)OR^(x) ; and R³ is hydrogen, hydroxy,acetoxy, --OCH₂ (OCH₂)_(m) OP(O)(OH)₂ or --OC(O)OR^(x) ; and R^(x) is aspreviously defined. In a more preferred embodiment R¹ is hydroxy or--OC(O)OR^(x) and R^(x) is preferably C₁₋₆ alkyl; and R³ is hydroxy oracetoxy.

In another preferred embodiment, the present invention provides compoundof formula (I) in which R³ is --OCH₂ (OCH₂)_(m) OP(O)(OH)₂ ; R¹ ishydroxy or --OC(O)OR^(x) ; R^(2') is hydrogen, and R² is hydrogen,hydroxy or --OC(O)OR^(x) ; and R^(x) is as previously defined. In a morepreferred embodiment, R¹ is hydroxy or --OC(O)OR^(x), and R^(x) ispreferably C₁₋₆ alkyl. In another more preferred embodiment, R² ishydroxy.

In another preferred embodiment, m is 0, 1 or 2 when thephosphonooxymethoxy group is present on the C7 of the taxane moiety.

The preferred pharmaceutically acceptable salts of a compound of formula(A) are alkali metal salts including lithium, sodium and potassiumsalts; and amine salts including triethylamine, triethanolamine,ethanolamine, arginine, lysine and N-methylglucamine salts. Even morepreferred salts are sodium, triethanolamine, and N-methylglucaminesalts.

The most preferred embodiments of taxane derivatives of formula (A)include the following compounds: (1) 7-O-phosphonooxymethylpaclitaxel,(2) 2'-O-(ethyloxycarbonyl)-7-O-phosphonooxymethylpaclitaxel; (3)2'-O-phosphonooxymethylpaclitaxel; (4)2',7-bis-O-(phosphonooxymethyl)paclitaxel; (5)3'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-furyl)-2'-O-ethyloxycarbonyl-7-O-phosphonooxymethylpaclitaxel;(6)3'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-thienyl)-2'-O-ethyloxycarbonyl-7-O-phosphonooxymethylpaclitaxel;(7)10-desacetyl-3'-N-desbenzoyl-3'-N-(t-butyloxycarbonyl)-10-O-(phosphonooxymethyl)paclitaxel;(8) 2'-O-phosphonooxymethoxymethylpaclitaxel; (9)2'-O-n-propylcarbonyl-7-O-phosphonooxymethylpaclitaxel; (10)2'-O-methylcarbonyl-7-O-phosphonooxymethylpaclitaxel; (11)2'-O-methoxycarbonyl-7-O-phosphonooxymethylpaclitaxel; (12)2'-O-phosphonooxymethoxymethyl-7-O-phosphonooxymethylpaclitaxel; andtheir respective pharmaceutically acceptable salts, particularly thesodium, potassium, arginine, lysine, N-methylglucamine, ethanolamine,triethylamine and triethanolamine salts.

Compounds of formula (A) may be prepared from a taxane derivativestarting material T-[OH]_(n) wherein T and n are as previously defined.The identity of T-[OH]_(n) is not particularly limited so long as thereis at least one reactive hydroxy group present on either the taxanemoiety or the C13 side chain to allow the formation ofphosphonooxymethyl ether linkage. It is to be understood that thereactive hydroxy group may be directly attached to the C13 propanoyloxybackbone (e.g. the 2'-hydroxy group of paclitaxel) or to the taxane coreframework (e.g. the 7-hydroxy group of paclitaxel); or it may be presenton a substituent on the C13 sidechain, or on a substituent on the taxanecore. The reaction sequence shown in Scheme I may be used to preparecompounds of formula (A) ##STR10##

In Scheme I T' is a taxane derivative in which non-reacting hydroxygroups have been blocked; R^(y) is a phosphono protecting group; n and mare as previously defined. Thus an appropriately protected T' having oneor more reactive hydroxy groups is first converted to a correspondingmethylthiomethyl ether of formula (B). Using paclitaxel as an example,T' may be paclitaxel itself (to effect 2',7-bismethylthiomethylation),7-O-triethylsilylpaclitaxel, 7-O-benzyloxycarbonylpaclitaxel, or2'-O-ethoxycarbonylpaclitaxel. A compound of formula (B) where m is 0may be prepared by treating T'-[OH]_(n) with dimethylsulfoxide/aceticanhydride, or with dimethylsulfide and an organic peroxide. Thesereactions are discussed more fully in a subsequent section.

The MTM ether having one intervening methyleneoxy unit (i.e. compoundsof formula (B) where m=1) may be prepared by several possible routes. Inone a compound of formula (B) where m=0 is reacted withN-iodosuccinimide (NIS) and methylthiomethanol to extend the chain byone methyleneoxy unit. ##STR11## An analogous reaction of an alcoholwith methylthiomethyloxy group in the presence of NIS was reported byVeeneman et al, in Tetrahedron, 1991, v47, pp. 1547-1562, the relevantportions thereof are hereby incorporated by reference. Silver triflateis preferably used as a catalyst. The compound of methylthiomethanol andits preparation is reported in Syn. Comm., 1986, 16 (13): 1607-1610.

In an alternative method, the T-alkoxide (Ad) generated by treating acompound of formula (Aa) with a base such as n-butyl lithium, lithiumdiisopropylamide or lithium hexamethyldisilazide, is reacted withchloromethyl methylthiomethyl ether to provide a compound of formula (B)in which m=1. ##STR12##

Compound (Ae) is prepared by reacting methylthiomethoxide (obtained frommethythiomethanol by treatment with a base such as n-butyl lithium,lithium diisopropylamide or lithium hexamethyldisilazide) withchloroiodomethane. Compound (Ae) may also be prepared by treating1,1'-dichlorodimethylether (ClCH₂ OCH₂ Cl) with a stoichiometric amountor less (e.g. about 0.8 equivalent) of sodium iodide followed by sodiumthiomethoxide. 1,1'-Dichlorodimethyl ether is reported in Ind. J. Chem.,1989, 28B, pp. 454-456.

In another method, a compound of formula (Aa) is reacted withbis(MTM)ether, CH₃ SCH₂ OCH₂ SCH₃, and NIS to give a compound of formula(B) in which m=1.

    T'-[OH].sub.n +n CH.sub.3 SCH.sub.2 OCH.sub.2 SCH.sub.3 →T'-[OCH.sub.2 OCH.sub.2 SCH.sub.3 ].sub.n

Bis(MTM)ether is prepared by reacting 1,1'-dichlorodimethyl ether withsodium iodide followed by sodium thiomethoxide.

The procedure described above using methylthiomethanol and NIS may beapplied to any reagent having an MTM group to extend the chain by onemethyleneoxy unit at a time. For example, a compound of formula (B)wherein m=1 can be reacted with methythiomethanol and NIS to provide acompound of formula (B) wherein m=2. The process may be repeated toprovide compounds of formula (B) in which m is 3, 4, 5 or 6.

In the second step shown in Scheme I, the methylthiomethyl ether isconverted to the corresponding protected phosphonooxymethyl ether. Thisis accomplished by treating the MTM ether with NIS and protectedphosphate HOP(O)(OR^(y))₂. In the third step, the phosphono protectinggroup and any hydroxy protecting group(s) are removed to provide acompound of formula (A). For example, a suitable phosphono protectinggroup is benzyl which may be removed by catalytic hydrogenolysis;hydroxy protecting groups such as trialkysilyl may be removed byfluoride ion, trichloroethoxycarbonyl may be removed by zinc. Removal ofprotecting groups are taught in textbooks such as Green and Wuts,Protective Groups in Organic Synthesis, John Wiley & Sons, 1991; andMcOmie, Protective in Organic Chemistry, Plenum Press, 1973. Both stepsare discussed in detail in a later section in the specification.

A variation of the reaction sequence shown in Scheme I is provided inScheme II. ##STR13##

In Scheme II, a compound of formula (Aa) is reacted with a compound offormula (Ca) and NIS to give a compound of formula (C), which is thendeblocked to give a compound of formula (A). Compounds of formula (Ca)in which m is 0 may be prepared by first treating methylthiomethanolwith a base such as Na, Li or K hexamethyldisilazide to givemethylthiomethoxide; the methoxide is then reacted with a protectedchlorophosphate such as dibenzyl chlorophosphate to provide the desiredcompound. Compounds of formula (Ca) in which m is 1 may be prepared bytreating CH₃ SCH₂ OCH₂ Cl with a diprotected phosphate salt, e.g.sodium, potassium, tetra(n-butyl)ammonium salts of dibenzyl phosphate;or CH₃ SCH₂ OCH₂ Cl may be first converted to the corresponding iodocompound using sodium iodide prior to reacting with the phosphate salt.Alternatively, compounds of formula (Ca) in which m is 1 may be preparedby treating ClCH₂ OCH₂ Cl with sodium iodide followed by sodiumthiomethoxide to provide CH₃ SCH₂ OCH₂ SCH₃ ; this compound is thentreated with NIS and a diprotected phosphate such as dibenzyl phosphateto give the desired product. Any of the previously mentioned reagentshaving a MTM group may be extended one methyleneoxy unit at a time byreacting said reagent with methylthiomethanol and NIS.

In another method for preparing a compound of formula (A), T-alkoxide(Ad) is reacted with an iodophosphate as shown in Scheme III. ##STR14##

In Scheme III, the iodophosphate compound is obtained by reacting ClCH₂(OCH₂)_(m) Cl with a diprotected phosphate salt to give ClCH₂ (OCH₂)_(m)OP(O)(OR^(y))₂ which is then treated with sodium iodide to give thedesired product.

Yet another method suitable for preparing a subset of compounds offormula (A) in which at least one of the phosphonooxymethoxy groups islinked to the taxane moiety is shown in Scheme IV. ##STR15##

In Scheme IV, m and n are as previously defined; X is a non-hydrogengroup, P is a hydroxy protecting group; txn is a taxane moiety.Compounds of formula (D) are taxanes having a 13α-hydroxy group and oneor more methylthiomethyl ether linked directly or indirectly to thetaxane core; also included are C13 metal alkoxides of formula (D). Anexample of a compound of formula (D) is 7-O-methylthiomethylbaccatinIII: ##STR16## The coupling of the taxane (D) with the azetidinone isanalogous to the one shown in Scheme VI, infra; thus the proceduredescribed there for the preparation of a compound of formula (Id) isalso applicable to the preparation of a compound of formula (Ba) [i.e. acompound of formula (B) in which at least one of the MTM group is linkeddirectly or indirectly to the taxane moiety], if a compound of formula(D) is used in place of a compound of formula (II) in Scheme VI. Thetaxane (D) is preferably first converted to a C13 metal alkoxide such assodium, potassium or lithium alkoxide; lithium alkoxide is preferred.The azetidinone serves as the precursor of the C13 sidechain. After thecoupling reaction with a taxane, the hydroxy protecting group P isremoved, and if desired, the free hydroxy group on the sidechain may beconverted to the MTM ether or derivatized to an ester or a carbonate asherein described.

The azetidinone may be prepared by methods described later which arealso methods generally known in the art. Compounds of formula (D) may beprepared by the general procedure described above for the preparation ofcompounds of formula (B) using a suitably protected taxane. However,more conveniently, they can be obtained from a compound of formula (Ba)by cleaving the 13-sidechain using a borohydride such as sodium ortetrabutylammonium borohydride; for example, 7-O-MTM of paclitaxel istreated with tetrabutylammoniumborohydride to give 7-O-MTM baccatin III.

The general process of Scheme I for the preparation of a compound offormula (A) is more particularly exemplified in Scheme V whichillustrates the preparation of a compound of formula (I') (i.e. acompound of formula (I) in which m is 0). The procedure employed in thissynthetic sequence is generally applicable to other taxane derivativesnot specifically encompassed by formula (I). Furthermore, the procedurein Scheme (V) may be modified in accordance with teachings containedherein by one skilled in the art to arrive at taxane derivatives offormula (A) in which m is 1, 2 or 3.

It is to be understood that in Scheme V as well as elsewhere in thespecification, the term "hydroxy protecting group" may encompasssuitable carbonates (e.g. --OC(O)OR^(x) in which R^(x) does not containhydroxy); thus, when a carbonate is used as a hydroxy protecting group,it is intended to be removed in a later step to generate the freehydroxy group, otherwise, the carbonate moiety remains as part of thefinal product. ##STR17##

In Scheme V, R^(1a) is hydroxy, protected hydroxy, --OC(O)R^(x) or--OC(O)OR^(x) ; R^(2') is hydrogen, and R^(2a) is hydrogen, hydroxy,protected hydroxy, --OC(O)R^(x) or --OC(O)OR^(x) ; R^(3a) is hydrogen,hydroxy, protected hydroxy, C₁₋₆ alkyloxy, --OC(O)R^(x) or --OC(O)OR^(x); one of R^(6a) or R^(7a) is hydrogen and the other is hydroxy,protected hydroxy or C₁₋₆ alkanoyloxy; or R^(6a) and R^(7a) togetherform an oxo group; with the proviso that at least one of R^(1a), R^(2a)or R^(3a), R^(6a) or R^(7a) is hydroxy. R^(1b) is hydroxy, protectedhydroxy, --OCH₂ SCH₃, --OC(O)R^(x) or --OC(O)OR^(x) ; R^(2') ishydrogen, and R^(2b) is hydrogen, hydroxy, protected hydroxy, --OCH₂SCH₃, --OC(O)R^(x) or --OC(O)OR^(x) ; R^(3b) is hydrogen, hydroxy,protected hydroxy, C₁₋₆ alkyloxy, --OC(O)R^(x), --OCH₂ SCH₃ or--OC(O)OR^(x) ; one of R^(6b) or R^(7b) is hydrogen and the other ishydroxy, protected hydroxy, C₁₋₆ alkanoyloxy or --OCH₂ SCH₃ ; or R^(6b)and R^(7b) together form an oxo group; with the proviso that at leastone of R^(1b), R^(2b), R^(3b), R^(6b) or R^(7b) is --OCH₂ SCH₃. R^(1c)is hydroxy, protected hydroxy, --OCH₂ OP(O)(OR^(y))₂, --OC(O)R^(x) or--OC(O)OR^(x) ; R^(2') is hydrogen, and R^(2c) is hydrogen, hydroxy,protected hydroxy, --OCH₂ OP(O)(OR^(y))₂, --OC(O)R^(x) or --OC(O)OR^(x); R^(3c) is hydrogen, hydroxy, protected hydroxy, C₁₋₆ alkyloxy,--OC(O)R^(x), --OCH₂ OP(O)(OR^(y))₂ or --OC(O)OR^(x) ; one of R^(6c) orR^(7c) is hydrogen and the other is hydroxy, protected hydroxy, C₁₋₆alkanoyloxy or --OCH₂ OP(O)(OR^(y))₂ ; with the proviso that at leastone of R^(1c), R^(2c), R^(3c), R^(6c) or R^(7c) is --OCH₂OP(O)(OR^(y))₂. R^(1') is hydroxy, --OCH₂ OP(O)(OH)₂, --OC(O)R^(x) or--OC(O)OR^(x) ; R^(2"') is hydrogen, and R^(2") is hydrogen, hydroxy,--OCH₂ OP(O)(OH)₂, --OC(O)R^(x) or --OC(O)OR^(x) ; R^(3') is hydrogen,hydroxy, C₁₋₆ alkyloxy, --OC(O)R^(x), --OCH₂ OP(O)(OH)₂ or --OC(O)OR^(x); one of R^(6') or R^(7') is hydrogen and the other is hydroxy, C₁₋₆alkanoyloxy or --OCH₂ OP(O)(OH)₂ ; with the proviso that at least one ofR^(1'), R^(2"), R^(3'), R^(6') or R^(7') is --OCH₂ OP(O)(OH)₂. R⁴, R⁵,R^(x), and p are as defined previously, and R^(y) is a phosphonoprotecting group.

In the first step, the free hydroxy group of a compound of formula (Ia)is converted to the corresponding methylthiomethyl ether (--OCH₂ SCH₃)group. This conversion may be accomplished by either one of the twoprocedures (1a--the dimethylsulfide method) and (1b--thedimethylsulfoxide method). The dimethylsulfide method for convertingalcohols to methylthiomethyl ethers is reported in Medina et al, Tet.Lett., 1988, pp. 3773-3776, the relevant portions thereof are herebyincorporated by reference. The dimethylsulfoxide method is thewell-known reaction commonly known as the Pummerer reaction.

It should be noted that the reactivity of a hydroxy group differsdepending on its location on the taxane derivative starting material offormula (Ia). Although in general the 2'-hydroxy group is more reactivein acylation reactions than the 7-hydroxy group which in turn is morereactive than the 10-hydroxy group, it has been found that, surprisinglywith the dimethylsulfide method, the 7-hydroxy is more readily convertedinto the methylthiomethyl ether than the 2'-hydroxy group. The tertiaryhydroxy group at C-1 is usually the least reactive. The difference inhydroxy reactivity may be exploited in controlling the site and degreeof methylthiomethylation.

Thus with a compound of formula (Ia) wherein R^(1a) and R^(2a) are bothhydroxy, the predominant methylthiomethylation product is thecorresponding 7-O-methylthiomethyl ether with the dimethylsulfidemethod. In order to obtain a compound of formula (Ib) wherein R^(1b) ismethylthiomethoxy, without also converting the 7-hydroxy group, ifpresent, into a methylthiomethyl ether, the 7-hydroxy group is blockedwith a conventional hydroxy protecting group such as triethylsilyl orbenzyloxycarbonyl. Similarly, 10-methylthiomethyl ether may be obtainedwithout also converting the 7- and/or 2'-hydroxy groups, if present,when the latter groups are blocked by the same of different hydroxyprotecting groups. Even though the 7-hydroxy is the preferentialmethylthiomethylation site in the dimethylsulfide method, it is stillpreferable to protect the 2'-hydroxy group if the 7-monomethylthiomethylether is the desired product.

Moreover, the reaction conditions may be manipulated to favor theformation of bis- or tris-methylthiomethyl ether taxane derivatives. Forexample, in the case of paclitaxel, increasing reaction time or using alarger excess of the methylthiomethylating reagents can result in ahigher ratio of 2',7-bis(methylthiomethyl) ether paclitaxel in theproduct mixture.

Returning now to Scheme V, in procedure (1a) a compound of formula (Ia)is treated with dimethylsulfide and an organic peroxide such as benzoylperoxide. The reaction is carried out in an inert organic solvent suchas acetonitrile, methylene chloride and the like at a temperatureconducive to product formation; typically the reaction is carried at atemperature range of from about -40° C. to about ambient temperature.Dimethylsulfide and benzoyl peroxide are used in excess relative to thetaxane derivative starting material (Ia), and dimethylsulfide is used inexcess relative to benzoyl peroxide.

The relative amounts of starting materials used will depend on thedegree of methylthiomethylation to be achieved. Thus when one freehydroxy group of the taxane derivative starting material (Ia) is to beconverted to the methylthiomethyl ether, dimethylsulfide and benzoylperoxide may be used in up to 10 fold excess relative to taxanederivative (Ia); and preferably, dimethylsulfide is used in about two tothree fold excess relative to benzoyl peroxide. In the case where thestarting material (Ia) has both 2'- and 7-hydroxy groups, the amount of2',7-bis(methylthiomethyl)ether obtained increases with the relativeamounts of dimethylsulfide and benzoyl peroxide. When2',7-bis(methylthiomethyl) ether is the desired product, dimethylsulfideis preferably used in about 15 to about 20 fold excess of the taxanederivative starting material; and benzoyl peroxide is used in about 5 toabout 10 fold excess relative to the taxane derivative startingmaterial.

Alternatively, a compound of formula (Ib) may be prepared by reacting acompound of formula (Ia) with dimethylsulfoxide and acetic anhydride(procedure 1b). This procedure is suitable for derivatizing anon-2'-hydroxy group into its methylthiomethyl ether. In procedure (1b),a compound of formula (Ia) is dissolved in dimethylsulfoxide and aceticanhydride is added to the solution. The reaction is usually carried outat room temperature, and for 18-24 hours to produce themonomethylthiomethyl ether.

In the second step of the reaction sequence, the methylthiomethyl etheris converted to the corresponding protected phosphonooxymethyl ether.The methylthiomethyl to protected phosphonooxymethyl conversion may beaccomplished by the general method reported in Veeneman et al,Tetrahedron, 1991, v47, pp. 1547-1562, the relevant portions thereof arehereby incorporated by reference. Thus, a compound of formula (Ib) withat least one methylthiomethyl ether group is treated withN-iodosuccinimide and a protected phosphoric acid such as dibenzylphosphate. The reaction is carried out in an inert organic solvent suchas tetrahydrofuran or a halogenated hydrocarbon such as1,2-dichloroethane or methylene chloride, and optionally in the presenceof a dehydrating agent such as molecular sieves. A catalyst such assilver trifluoromethanesulfonate may also be added to accelerate thereaction. The reaction is carried out at a temperature ranging fromabout 0° C. to about room temperature, preferably at room temperature.N-Iodosuccinimide and the protected phosphoric acid are used in aboutthe same molar equivalent as the methylthiomethylether (Ib), butpreferably they are used in slight excess, for example about 1.3 toabout 1.5 equivalents relative to compound of formula (Ib).

In the third step of the reaction sequence, the phosphono protectinggroup and hydroxy protecting group, if present, are removed. Thedeblocking is accomplished by conventional methods well known in the artsuch as acid- or base-catalyzed hydrolysis, hydrogenolysis, reduction,and the like. For example, catalytic hydrogenolysis can be used toremove the benzyl phosphono protecting group as well as thebenzyloxycarbonyl hydroxy protecting group. Deprotecting methodologiesmay be found in standard texts such as Greene and Wutz, or McOmie,supra. Needless to say if a compound of formula (Ia) contains hydroxygroups in radical R^(x), said hydroxy groups are preferably protectedwith suitable hydroxy protecting groups until deprotected in this laststep.

As indicated earlier the procedure in Scheme V may be modified inaccordance with the teaching contained herein by one skilled in the artto arrive at taxane derivatives of formula A in which m is 1, 2 or 3. Asexamples, Schemes Va and Vb specifically illustrate how one skilled inthe art can modify the teaching contained herein to arrive at certaincompounds of formula A wherein at least one substitutent is --OCH₂(OCH₂)₂ OP(O)(OH)₂. Similarly other compounds of formula A in which m is3 can be readily obtaiined. ##STR18##

The base salts of a compound of formula (I) may be formed byconventional techniques involving contacting a compound of formula (I)free acid with a metal base or with an amine. Suitable metal basesinclude hydroxides, carbonates and bicarbonates of sodium, potassium,lithium, calcium, barium, magnesium, zinc, and aluminum; and suitableamines include triethylamine, ammonia, lysine, arginine,N-methylglucamine, ethanolamine, procaine, benzathine, dibenzylamine,tromethamine (TRIS), chloroprocaine, choline, diethanolamine,triethanolamine and the like. The base salts may be further purified bychromatography followed by lyophilization or crystallization.

TAXANE DERIVATIVES STARTING MATERIALS

The processes described above may be applied to any taxane derivativesof the formula T-[OH]_(n) to form compounds of formula (A). Manyexamples of T-[OH]_(n) have been reported in the literature and some ofwhich are listed below. (a) paclitaxel; (b) Taxotere®; (c)10-desacetylpaclitaxel; (d) taxane derivatives disclosed in PCTapplication 93/06079 (published Apr. 1, 1993) having the formula##STR19## wherein R₁ is --OR₆, --SR₇, or --NR₈ R₉ ; R₂ is hydrogen,alkyl, alkenyl, alkynyl, aryl, or heteroaryl; R₃ and R₄ areindependently hydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl, oracyl, provided, however, that R₃ and R₄ are not both acyl; R₅ is--COR₁₀, --COOR₁₀, --COSR₁₀, --CONR₈ R₁₀, --SO₂ R₁₁, or --POR₁₂ R₁₃ ; R₆is hydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl, hydroxyprotecting group, or a functional group which increases the watersolubility of the taxane derivative; R₇ is alkyl, alkenyl, alkynyl,aryl, heteroaryl, or sulfhydryl protecting group; R₈ is hydrogen, alkyl,alkenyl, alkynyl, aryl, heteroaryl; R₉ is an amino protecting group; R₁₀is alkyl, alkenyl, alkynyl, aryl, heteroaryl; R₁₁ is alkyl, alkenyl,alkynyl, aryl, heteroaryl, --OR₁₀, or --NR₈ R₁₄ ; R₁₂ and R₁₃ areindependently alkyl, alkenyl, alkynyl, aryl, heteroaryl, --OR₁₀, or--NR₈ R₁₄ ; R₁₄ is hydrogen, alkyl, alkenyl, alkynyl, aryl, heteroaryl;R₁₅ and R₁₆ are independently hydrogen, hydroxy, lower alkanoyloxy,alkenoyloxy, alkynoyloxy, aryloyloxy or R₁₅ and R₁₆ together form anoxo; R₁₇ and R₁₈ are independently hydrogen, hydroxy, lower alkanoyloxy,alkenoyloxy, alkynoyloxy, aryloyloxy or R₁₇ and R₁₈ together form anoxo; R₁₉ and R₂₀ are independently hydrogen or hydroxy or loweralkanoyloxy, alkenoyloxy, alkynoyloxy, or aryloyloxy; R₂₁ and R₂₂ areindependently hydrogen or lower alkanoyloxy, alkenoyloxy, alkynoyloxy,or aryloyloxy or R₂₁ and R₂₂ together form an oxo; R₂₄ is hydrogen orhydroxy or lower alkanoyloxy, alkenoyloxy, alkynoyloxy, or aryloyloxy;or R₂₃ and R₂₄ together form an oxo or methylene or R₂₃ and R₂₄ togetherwith the carbon atom to which they are attached form an oxirane ring orR₂₃ and R₂₂ together with the carbon atom to which they are attachedform an oxetane ring; R₂₅ is hydrogen, hydroxy, or lower alkanoyloxy,alkenoyloxy, alkynoyloxy, or aryloyloxy; or R₂₆ is hydrogen, hydroxy, orlower alkanoyloxy, alkenoyloxy, alkynoyloxy, or aryloyloxy; or R₂₆ andR₂₅ taken together form an oxo; and R₂₇ is hydrogen, hydroxy or loweralkoxy, alkanoyloxy, alkenoyloxy, alkynoyloxy, or aryloyloxy; (e) taxanederivatives disclosed in U.S. Pat. No. 5,227,4003'-desphenyl-3'-(2-furyl) or 3'-(2-thienyl) derivatives of paclitaxel,Taxotere®; (f) taxane derivatives disclosed in EP 534,709 published Mar.31, 1993 (paclitaxel derivatives in which the sidechain phenyl groupsare independently replaced with naphthyl, styryl or substituted phenyl).See also PCT 92/09589 published Jun. 11, 1992; (g) taxane derivativesdisclosed in EP 534,707 published Mar. 31, 1993 (paclitaxel derivativesin which the 3'-N-benzoyl group is replaced with ethoxycarbonyl ormethoxycarbonyl); (h) PCT Application 93/06093 published Apr. 1, 1993(10-desacetoxy derivatives of paclitaxel and Taxotere®); (i) EP 524,093published Jan. 20, 1993 (10-, 7-, or 7,10-bis-O-(N-substituted carbamoyltaxane derivatives); (j) 9-α-hydroxy analog of paclitaxel is disclosedin Klein, "Synthesis of 9-Dihydrotaxol: A New Bioactive Taxane,"Tetrahedron Letters, 1993, 34(13):2047-2050; (k) 14-β-hydroxy analog ofpaclitaxel and Taxotere® prepared from 14β-hydroxy-10-deacetylbaccatinIII are disclosed at the 205th ACS National Meeting in Colorado, 1993.(Med. Chem. Division, Abstract No. 28); and (1) other taxanes, such asC7-fluorotaxanes and various C10-substituted taxanes, as disclosed inEuropean Patent Application 577,082A1 published Jan. 5, 1994, which isherein incorporated by reference in its entirety.

The free hydroxy group or groups of taxane derivatives may be convertedby conventional methods to the corresponding ester or carbonate; forexample in compounds of formula (Ia) one of R^(1a), R^(2a) or R^(3a) is--OC(O)R^(x) or --OC(O)OR^(x) and R^(x) is as previously defined. Thus,a taxane derivative T-OH may be reacted with a compound of the formulaL-C(O)OR^(x) (L being a leaving group) such as a chloroformate in thepresence of a base such as tertiary amine to give the correspondingcarbonate; for example, paclitaxel reacts with ethyl chloroformate inthe presence of diisopropylethylamine to provide2'-O-ethyloxycarbonylpaclitaxel. T-OH may also react with a carboxylicacid R^(x) CO₂ H or an acylating equivalent thereof (e.g. an anhydride,active ester or an acyl halide) to provide the corresponding ester.Needless to point out when R^(x) in L-C(O)OR^(x), or R^(x) CO₂ H or anacylating equivalent thereof contains hydroxy groups, they arepreferably protected with suitable hydroxyprotecting groups.

Additionally, taxane derivatives T-[OH]_(n) may be prepared by acylatinga taxane moiety having a C13-hydroxy group with an appropriatelysubstituted 3-amino-2-hydroxypropanoic acid, an acylating equivalentthereof, or a precursor thereof. Suitable precursors of substitutd3-amino-2-hydroxypropanoic acid are for example azetidinones of formula(III). This acylation reaction is exemplified in the coupling of hydroxyprotected baccatin III or hydroxyprotected 10-deacetylbaccatin III and aphenylisoserine derivative to give paclitaxel derivatives as disclosedin e.g. Denis et al, U.S. Pat. Nos. 4,924,011 and 4,924,012; and in thecoupling of a protected baccatin III and an azetidinone to givepaclitaxel and derivatives thereof as disclosed in EP PublishedApplication 400,971 published Dec. 5, 1990 (now U.S. Pat. No. 5,175,315)and U.S. Pat. No. 5,229,526.

The process as disclosed in EP 400,971 (the Holton process) involvesreacting 1-benzoyl-3-(1-ethoxy)ethoxy-4-phenyl-2-azetidinone with7-O-triethylsilylbaccatin III in the presence ofN,N-dimethylaminopyridine and pyridine at 25° C. for 12 hours;paclitaxel is obtained after the various hydroxyprotecting groups areremoved. An improvement of the Holton process is reported by Ojima et alin "New and Efficient Approaches to the Semisynthesis of Taxol and itsC-13 Side Chain Analogs by Means of β-Lactam Synthon Method"Tetrahedron, 1992, 48(34):6985-7012. Ojima's process involves firstgenerating the sodium salt of 7-triethylsilylbaccatin III with sodiumhydride; this salt is then reacted with chiral1-benzoyl-3-(1-ethyoxy)ethoxy-4-phenyl-2-azetidinone to providepaclitaxel after removal of the hydroxy protecting groups. In U.S. Pat.No. 5,229,526 Holton discloses the coupling of a metal alkoxide ofbaccatin III or a derivative thereof with a 2-azetidinone to providetaxanes with C13 sidechain. This process is said to be highlydiastereoselective; therefore racemic mixtures of the sidechainprecursor 2-azetidinone may be used. Recently, Ojima et al reported in"A Highly Efficient Route to Taxotere by the β-Lactam Synthon Method,"Tetrahedron Letters, 1993, 34(26):4149-4152, the coupling of metalalkoxides of 7,10-bis-O-(trichloroethoxycarbonyl)-10-deacetylbaccatinIII with chiral 1-(t-butoxycarbonyl)-4-phenyl-3-(protectedhydroxy)-2-azetidinone to give Taxotere® after deprotection. Therelevant portions of all references cited above are hereby incorporatedby reference.

The baccatin/azetidinone process generalized to the preparation ofcompounds of formula (Ia) is illustrated in Scheme VI. Again, othertaxane derivatives not specifically encompassed within the formula (Ia)may also be prepared by this process by employing appropriate startingmaterials. ##STR20##

In Scheme VI, R^(2') is hydrogen, and R^(2d) is hydrogen, protectedhydroxy, --OC(O)R^(x) or --OC(O)OR^(x) ; R^(3d) is hydrogen,--OC(O)R^(x), C₁₋₆ alkyloxy, protected hydroxy or --OC(O)OR^(x) ; one ofR^(6d) or R^(7d) is hydrogen and the other is hydroxy, protected hydroxyor C₁₋₆ alkanoyloxy; or R^(6d) and R^(7d) together form an oxo group; Pis a hydroxy protecting group; M is hydrogen or a Group IA metal such aslithium, sodium or potassium; and p, R⁴, R⁵ and R^(x) are as previouslydefined. The reaction may be conducted according to the proceduredisclosed in EP 400,971 wherein the baccatin III derivative of formula(II) wherein M is hydrogen is reacted with an azetidinone of formula(III) in the presence of an organic base such asN,N-dimethylaminopyridine. Preferably, however, the baccatin IIIderivative is first converted to a 13-alkoxide by treating the formerwith a strong base such as hydrides, alkylamides, andbis(trialkylsilyl)amides of Group IA metals as disclosed in U.S. Pat.No. 5,229,526 and the Ojima references, supra. More preferably, the13-alkoxide is a lithium alkoxide. The formation of a lithium salt maybe achieved by reacting a compound of formula (II) wherein M is hydrogenwith a strong metal base, such as lithium diisopropylamide, C₁₋₆alkyllithium, lithium bis(trimethylsilyl)amide, phenyllithium, lithiumhydride, or the like base. Needless to point out that if a compound offormula (II) contains hydroxy groups in radical R^(x), said hydroxygroups are preferably protected with suitable hydroxy protecting groups.

The coupling reaction between a taxane of formula (II) and anazetidinone of formula (III) is conducted in an inert organic solventsuch as tetrahydrofuran at reduced temperature in the range of about 0°C. to about -78° C. The azetidinones of formula (III) may be used as aracemic mixture to couple with taxane metal alkoxides of formula (II) inwhich M is a group 1A metal; in such case, the azetidinone reactant ispreferably used in at least 2 equivalents relative to the taxanereactant, and more preferably from about 3 to about 6 equivalents.Chiral azetidinones may also be used, and in such case one equivalent ofthe azetidinone relative to the taxane may be sufficient, but preferablythe azetidinone is used in slight excess, for example up to 1.5equivalents.

The hydroxy protecting groups may be the same or they may be chosen in amanner to allow the selective removal of one or more protecting groupswithout substantially affecting the others; for example, in a compoundof formula (Id), R^(2d) and PO may be both triethylsilyloxy, and R^(3d)may be benzyloxycarbonyl; catalytic hydrogenolysis in the presence ofpalladium on carbon removes the benzyloxycarbonyl protecting groupwithout removing the triethylsilyl group. Thus, the hydroxy protectinggroups of a compound of formula (Id) may be selectively removed toprovide a compound of formula (Ia).

Compounds of formula (II) are either known in the literature, e.gbaccatin III, 10-deacetylbaccatin III and their hydroxy protectedderivatives, or can be prepared from the known compounds by conventionalconventional methods, e.g converting a hydroxy group to a carbonate.Additional compounds of formula (II) may be prepared according toprocedures described hereinbelow in the section PREPARATION OF STARTINGMATERIALS.

Compounds of formula (III) can be prepared from a compound of (IIIa)according to the general method described in EP 400,971 and Ojima et al,Tetrahedron, 48:6985-7012, 1992. ##STR21## Thus a compound of formula(IIIa) is first treated with a base such as n-butyllithium ortriethylamine, and then followed by a compound of the formula R⁴ (O)_(p)CO-L where L is a leaving group to provide a compound of formula (III).

Compounds of (IIIa) may be prepared according to the general methoddisclosed in EP 400,971 by going through an intermediate compound3-acetoxy-4-substituted-2-azetidinone (IIIb); or by the method disclosedin U.S. Pat. No. 5,229,526 by going through an intermediate compound3-triethylsilyloxy-4-substituted-2-azetidinone. In an improved process acompound (IIIb) may be obtained by condensing acetoxyacetyl chloridewith a bis-imine followed by hydrogenolysis or acid cleavage to removethe N-imine group; this process is shown in the following scheme inwhich R^(5') is an optionally substituted aryl or a heteroaryl groupsuch as furyl or thienyl. This process is disclosed in co-pendingapplication U.S. Ser. No. 08/165,610 filed Dec. 13, 1993 which is herebyincorporated by reference. ##STR22##

The products (IIIb) obtained from these cycloaddition reactions areusually a racemic mixture of the two cis-azetidinones. The racemicmixture may be resolved by conventional methods such as conversion todiastereomers, differential absorption on column packed with chiraladsorbents, or enzymatically. For example, a racemic mixture ofcompounds of formula (IIIb) may be contacted with an enzyme thatcatalyzes the hydrolysis of an ester, for example an esterase or alipase, to selectively cleave the 3-acyl group of one enantiomer withoutaffecting the other. (See e.g. Brieva et al, J. Org. Chem., 1993,58:1068-1075; also co-pending application U.S. Ser. No. 092,170 filedJul. 14, 1993, European Patent Application Number 552041, published Jul.21, 1993). Alternatively, the racemic mixture may be first subjected tobase-catalyzed hydrolysis to remove the 3-acyl group and to generate aracemic mixture of the corresponding 3-hydroxy β-lactam; the racemicmixture of 3-hydroxy β-lactam is then contacted with an enzyme capableof catalyzing acylation of an hydroxy group to selectively acylate thehydroxy group of one enantiomer without affecting the other. Or theracemic mixture of 3-hydroxy β-lactam may be acylated with a chiralcarboxylic acid, and the resulting diastereomeric mixture may then beseparated using methods known in the art, and the chiral auxiliaryremoved to provide the desired enantiomer.

Ojima et al, in J. Org. Chem., 56:1681-1683, 1991; Tet. Lett.,33:5737-5740, 1992; and Tetrahedron, 48:6985-7012, 1992 reported thesynthesis of a number of chiral azetidinones of formula (IIIa) and/orthe corresponing N-(p-methoxyphenyl) congener; wherein P is the hydroxyprotecting group triisopropylsilyl; and R⁵ is 4-methoxyphenyl,3,4-dimethyoxyphenyl, phenyl, 4-fluorophenyl, 4-trifluoromethylphenyl,2-furyl, 2-phenylethenyl, 2-(2-furyl)ethenyl, 2-methylpropyl,cyclohexylmethyl, isopropyl, phenethyl, 2-cyclohexylethyl, or n-propyl.Other references for making azetidinones fo formula (IIIa) and/or (III)can be found in European Patent Applications 0,534,709 A1, 0,534,708 A1,and 0,534,707 A1, all three published on Mar. 31, 1993; in PCTapplication WO 93/06079 published on Apr. 1, 1993; in Bioorganic andMedicinal Chemistry Letters, 3, No. 11, DP 2475-2478 (1993); also inBioorganic and Medicinal Chemistry Letters, 3, No. 11, pp 2479-2482(1993); in J. Org. Chem., 58, pp 1068-1075; in Tetrahedron Letters, 31,No. 44, pp 6429-6432 (1990); in Bioorganic and Medicinal ChemistryLetters, 3, No. 11, pp 2467-2470 (1993); European Application 552,041published on Jul. 21, 1993; and in our copending U.S. application Ser.No. 092,170 filed on Jul. 14, 1993. The relevant portions of allaforementioned references are hereby incorporated by reference. Otherazetidinones within the definition of formula (III) but are notspecifically disclosed in these references may be prepared by a personskilled in the art following the methodologies generally known in theart.

BIOLOGICAL EVALUATION

Compounds of formula (B) of the present invention are usefulintermediates for novel antitumor agents of formula (A). In addition,some compounds within the scope of formula (B), namely compounds offormula (B'), were themselves found to be antitumor agents. BiologicalSection I below demonstrates the antitumor activity of the compounds offormula (A). On the other hand, Biological Section II below demonstratesthe antitumor activity of the compounds of formula (B').

Biological Section I In Vitro Cytotoxicity Data

The compounds of formula (A) showed in vitro cytoxicity activity againsthuman colon carcinoma cells HCT-116 and HCT-116/VM46. The HCT-116/VM46cells are cells that have been previously selected for teniposideresistance and express the multi-drug resistance phenotype, includingresistance to paclitaxel. Cytotoxicity was assessed in HCT-116 humancolon carcinoma cells by XTT(2,3-bis(2-methoxy-4-nitro-5-sulfphenyl)-5-[(phenylamino)carbonyl]2H-tetrazoliumhydroxide) assay as reported in D. A. Scudiero, et al., "Evaluation ofsoluble tetrazolium/formazan assay for cell growth and drug sensitivityin culture using human and other tumor cell lines," Cancer Res.48:4827-4833, 1988. Cells were plated at 4000 cells/well in 96 wellmicrotiter plates and 24 hours later drugs were added and serialdiluted. The cells were incubated at 37° C. for 72 hours at which timethe tetrazolium dye, XTT, was added. A dehydrogenase enzyme in livecells reduces the XTT to a form that absorbs light at 450 nm which canbe quantitated spectrophotometrically. The greater the absorbance, thegreater the number of live cells. The results are expressed as an IC₅₀,which is the drug concentration required to inhibit cell proliferation(i.e., absorbance at 450 nm) to 50% of that of untreated control cells.The IC₅₀ values for representative compounds evaluated in this assay aregiven in Table I.

                  TABLE I                                                         ______________________________________                                        In vitro cytotoxicity data against human                                      colon carcinoma cells.                                                                    IC.sub.50 (μM)                                                 Compound.sup.1                                                                              HCT-116  HCT-116/VM46                                           ______________________________________                                        Taxotere ®                                                                              0.004    0.213                                                  paclitaxel    0.004    0.44                                                   Example 1     0.0158   1.24                                                   Example 3     0.312    6.25                                                   Example 4     0.0457   >6.3                                                   ______________________________________                                         .sup.1 Examples 1 and 4 as free acid; example 3 as sodium salt.          

The compound 7-O-methylthiomethylpaclitaxel (Example 1 (a) was alsotested in the cytotoxicity assay and it showed IC₅₀ of 0.003 μM againstHCT-116 and 0.025 μM against HCT-116/VM46.)

In Vivo Antitumor Activity

Balb/c×DBA₂ F₁ (CDF₁) hybrid mice were implanted subcutaneously (sc)with 0.1 ml of a 2% (w/v) brei of M109 lung carcinoma (as described inW. Rose "Evaluation of Madison 109 Lung Carcinoma as a Model forScreening Antitumor Drugs," Cancer Treatment Reports, 65, No. 3-4 pp.299-312 (1981). The test compounds and reference drug, paclitaxel, wereadministered intravenously to groups of mice; each group received acompound at a different dose level, and three or four different doselevels were evaluated per compound. Mice were followed daily forsurvival until their death or about day 75 post-tumor implant, whicheveroccurred first. One group of mice per experiment remained untreated andserved as the control. Tumors were also measured once or twice weeklyand the size in mm was used to estimate tumor weight according to thepublished procedure (ibid).

Median survival times of compound-treated (T) mice were compared to themedian survival time of parallel control (C) mice. The ratio of the twovalues for each compound-treated group of mice was multiplied by 100 andexpressed as a percentage (i.e., % T/C) in Table II for representativecompounds. Additionally, the difference between the median time fortreated groups and that for the control group to grow tumor to 1 gm,expressed as T-C values in days, is also shown in Table II. The greaterthe T-C value, the greater the delay in primary tumor growth. Compoundsshowing % T/C≧125% and/or T-C≧4.0 days are considered to be active inthe M109 SC model.

                  TABLE II                                                        ______________________________________                                                Maximum Effect Opt. Dose                                              Compound  % T/C       T-C (days)                                                                             (mg/kg/inj;)                                   ______________________________________                                        Example 1.sup.d                                                                         131         14.0     45.sup.a                                       paclitaxel                                                                              134         14       48/24.sup.a,c                                  Example 3.sup.d                                                                         160         18.8     24.sup.b                                       paclitaxel                                                                              151         15       18.sup.b                                       ______________________________________                                         .sup.a Compound was administered i.v. once daily, on days 4, 5, 6, 7 and      posttumor implant.                                                            .sup.b Compound was administered i.v. once daily, on days 5, 6, 7, 8 and      posttumor implant.                                                            .sup.c Higher dose achieved maximum increase in lifespan; lower dose          associated with causing maximum delay in tumor growth.                        .sup.d sodium salt.                                                      

Compound of Example 3 (as the triethanolamine salt) was furtherevaluated in murine and human xenograft tumor models (M109,A2780/cDDP--human ovarian carcinoma resistant to cisplatin, andHCT-116--human colon carcinoma) against paclitaxel as positive control.The A2780/cDDP model is described in Rose and Baslet, In Vivo, 1990,4:391-396; the HCT-116 model is described in Rose and Baslet, In Vivo,1989, 3:249-254. M109 was passaged sc biweekly in Balb/C mice andimplanted sc into CDF1 mice for antitumor evaluation. A2780/cDDP andHCT-116 were grown in athymic mice for both passage (every two to threeweeks) and therapy experiments. Compound of Example 3 was administerediv in water, or orally in water with a few drops of Tween 80, whilepaclitaxel was either suspended in water plus Tween 80, or dissolved incremophore/ethanol (50%/50%) and diluted with saline. The treatmentregimen for the sc M109 tumor tests was once daily for 5 consecutivedays beginning on Day 4 post tumor implant. For the human tumorxenograft tests, compounds were given once daily every other day forfive administrations beginning when the tumors were staged to between 50to 100 mg.

In one M109 experiment, compound of Example 3 administered iv achievedmax. % T/C of 155 (T-C of 19 days) at 36 mg/kg/inj. (cf. paclitaxel max.% T/C of 132 (T-C of 13 days) at 36 or 18 mg/kg/inj.). In the sameexperiment, compound of Example 3 administered orally achieved a max. %T/C of 158 (T-C of 22.8 days) at a dose of 160 mg/kg/adm. whilepaclitaxel at the same dose (highest tested) suspended in water andTween 80 did not show activity. In another M109 experiment, ivadministered compound of Example 3 produced max. % T/C of 170 (T-C of 17days) at 48 mg/kg/inj. (cf. paclitaxel max. % T/C of 167 (T-C of 14days) at 48 or 36 mg/kg/inj.). In the same experiment, orallyadministered compound of Example 3 produced max. % T/C of 172 (T-C of 17days) at a dose of 200 mg/kg/adm. while paclitaxel dissolved incremophore/ethanol/saline did not show activity at 60/mg/kg/inj. In thisexperiment, paclitaxel dissolved in cremophore/ethanol/saline could notbe administered at greater than 60/mg/kg/inj. due to solubility andtoxicity constraints.

In the A2780/cDDP experiment, iv administered compounds of Example 3showed max. T-C value of 29.8 days at 36 mg/kg/inj (cf. paclitaxel max.T-C of 26.3 days at 36 mg/kg/inj.). Orally administered compound ofExample 3 produced max. T-C of 20 days at a dose of 160 mg/kg/adm. Inthe HCT-116 experiment, iv treatment with 24 or 36 mg/kg/inj. ofpaclitaxel produced 6 cures of 7 or 6 cures of 8 treated mice,respectively, and 160 or 240 mg/kg/adm. of oral compound of Example 3cured 6 or 7 of 8 treated mice, respectively. Cure means tumor-free onDay 80 post tumor implant.

The triethanolamine salt of compound of example 1 was also found to haveoral activity in the M109 and HCT-116 models.

It is well appreciated in the art that there will be some, usuallyslight, variations in the anti-tumor activity depending on whatparticular salt form is employed.

The pharmaceutically acceptable salt of phosphonooxymethyl ethers oftaxane derivatives of formula (A) exhibit improved water solubility overpaclitaxel thereby allowing more convenient pharmaceutical formulations.Without being bound by theory, it is believed that thephosphonooxymethyl ethers of the present invention are prodrugs ofpaclitaxel or derivative thereof; the phosphonooxymethyl moiety beingcleaved upon contact with phosphatase in vivo to generate subsequentlythe parent compound.

Biological Section II Mice M109 Model

Balb/c×DBA/2 F₁ hybrid mice were implanted intraperitoneally, asdescribed by William Rose in Evaluation of Madison 109 Lung Carcinoma asa Model for Screening Antitumor Drugs, Cancer Treatment Reports, 65, No.3-4 (1981), with 0.5 mL of a 2% (w/v) brei of M109 lung carcinoma.

Mice were treated with compound under study by receiving intraperitonealinjections of various doses on either days 1, 5 and 9 post-tumor implantor days 5 and 8 post-implant. Mice were followed daily for survivaluntil approximately 75-90 days post-tumor implant. One group of mice perexperiment remained untreated and served as the control group. Mediansurvival times of compound-treated (T) mice were compared to the mediansurvial time of the control (C) mice. The ratio of the two values foreach compound-treated group of mice was multiplied by 100 and expressedas a percentage (i.e. % T/C) in Table III for representative compoundsof formula (B').

                  TABLE III                                                       ______________________________________                                        EXAMPLE            T/C (mg/kg/inj.;                                           NUMBER             schedule in days)                                          ______________________________________                                        14 (b)             143 (12; d. 5 + 9)                                         15                 192 (8; d. 5 + 9)                                          ______________________________________                                    

As shown above, compounds of formula (A) and (B') of the instantinvention are effective tumor inhibiting agents, and thus are useful inhuman and/or veterinary medicine. Thus, another aspect of the instantinvention concerns a method for inhibiting human and/or other mammaliantumors which comprises administering to a tumor bearing host anantitumor effective amount of a compound of formula (A) or (B').

Compounds of formulas (A) and (B') of the present invention may be usedin a manner similar to that of paclitaxel; therefore, an oncologistskilled in the art of cancer treatment will be able to ascertain,without undue experimentation, an appropriate treatment protocol foradministering a compound of the present invention. The dosage, mode andschedule of administration for compounds of this invention are notparticularly restricted, and will vary with the particular compoundemployed. Thus a compound of the present invention may be administeredvia any suitable route of administration, preferably parenterally; thedosage may be, for example, in the range of about 1 to about 100 mg/kgof body weight, or about 20 to about 500 mg/m². Compounds of formula (A)and (B') may also be administered orally; oral dosage may be in therange of about 5 to about 500 mg/kg of body weight. The actual dose usedwill vary according to the particular composition formulated, the routeof administration, and the particular site, host and type of tumor beingtreated. Many factors that modify the action of the drug will be takeninto account in determining the dosage including age, weight, sex, dietand the physical condition of the patient.

The present invention also provides pharmaceutical compositions(formulations) containing an antitumor effective amount of a compound offormula (A) or (B') in combination with one or more pharmaceuticallyacceptable carriers, excipients, diluents or adjuvants. Examples offormulating paclitaxel or derivatives thereof may be found in, forexample, U.S. Pat. Nos. 4,960,790 and 4,814,470, and such examples maybe followed to formulate the compounds of this invention. For example,compounds of the present invention may be formulated in the form oftablets, pills, powder mixtures, capsules, injectables, solutions,suppositories, emulsions, dispersions, food premix, and in othersuitable forms. They may also be manufactured in the form of sterilesolid compositions, for example, freeze dried and, if desired, combinedwith other pharmaceutically acceptable excipients. Such solidcompositions can be reconstituted with sterile water, physiologicalsaline, or a mixture of water and an organic solvent, such as propyleneglycol, ethanol, and the like, or some other sterile injectable mediumimmediately before use for parenteral administration.

Typical of pharmaceutically acceptable carriers are, for example,manitol, urea, dextrans, lactose, potato and maize starches, magnesiumstearate, talc, vegetable oils, polyalkylene glycols, ethyl cellulose,poly(vinylpyrrolidone), calcium carbonate, ethyl oleate, isopropylmyristate, benzyl benzoate, sodium carbonate, gelatin, potassiumcarbonate, silicic acid. The pharmaceutical preparation may also containnontoxic auxiliary substances such as emulsifying, preserving, wettingagents, and the like as for example, sorbitan monolaurate,triethanolamine oleate, polyoxyethylene monostearate, glyceryltripalmitate, dioctyl sodium sulfosuccinate, and the like.

In the following experimental procedures, all temperatures areunderstood to be in Centigrade (C) when not specified. The nuclearmagnetic resonance (NMR) spectral characteristics refer to chemicalshifts (δ) expressed in parts per million (ppm) versus tetramethylsilane(TMS) as reference standard. The relative area reported for the variousshifts in the proton NMR spectral data corresponds to the number ofhydrogen atoms of a particular functional type in the molecule. Thenature of the shifts as to multiplicity is reported as broad singlet(bs), broad doublet (bd), broad triplet (bt), broad quartet (bq),singlet (s), multiplet (m), doublet (d), quartet (q), triplet (t),doublet of doublet (dd), doublet of triplet (dt), and doublet of quartet(dq). The solvents employed for taking NMR spectra are acetone-d₆(deuterated acetone). DMSO-d₆ (perdeuterodimethylsulfoxide), D₂ O(deuterated water), CDCl₃ (deuterochloroform) and other conventionaldeuterated solvents. The infrared (IR) spectral description include onlyabsorption wave numbers (cm⁻¹) having functional group identificationvalue.

Celite is a registered trademark of the Johns-Manville ProductsCorporation for diatomaceous earth.

The abbreviations used herein are conventional abbreviations widelyemployed in the art. Some of which are: MS (mass spectrometry); HRMS(high resolution mass spectrometry); Ac (acetyl); Ph (phenyl); v/v(volume/volume); FAB (fast atom bombardment); NOBA (m-nitrobenzylalcohol); min (minute(s)); h or hr(s) (hour(s)); NIS(N-iodosuccinimide); BOC (t-butoxycarbonyl); CBZ or Cbz(benzyloxycarbonyl); Bn (benzyl); Bz (benzoyl); TES (triethylsilyl);DMSO (dimethylsulfoxide); THF (tetrahydrofuran); HMDS(hexamethyldisilazane).

PREPARATION OF STARTING MATERIALS

The preparations of several specific starting materials useful in thepreparation of compounds of formula (A) are exemplified below.

Preparation 1. 10-Desacetoxypaclitaxel ##STR23## (a)2',7-O-bis(2,2,2-trichloroethoxycarbonyl)-10-deacetyl paclitaxel

10-Deacetyl paclitaxel (140 mg, 0.173 mmol) in dry dichloromethane (3.5mL) was treated at 0° C. with pyridine (0.028 mL, 0.346 mmol) andtrichloroethyl chloroformate (0.0724 mL, 0.260 mmol). After 1 h at thistemperature, the cold bath was removed and the mixture was stirred atroom temperature overnight. The solvent was evaporated and the residuechromatographed on silica gel (30-50% ethyl acetate in hexane) to affordthe title compound as a foam (92.3 mg, 46%). Further elution affordedunreacted starting material (35 mg, 25%), and2',10-O-bis(2,2,2-trichloroethoxycarbonyl)-10-deacetylpaclitaxel in 16%yield.

(b)2',7-O-bis(2,2,2-trichloroethoxycarbonyl)-10-desacetoxy-11,12-dihydropaclitaxel-10,12(18)-diene

The product obtained in step (a) (92.3 mg, 0.079 mmol) in drydichloromethane (2 mL) was treated at room temperature with1,1,2-trifluoro-2-chlorotriethylamine (0.0384 mL, 0.238 mmol). Thesolution was stirred overnight. The solvent was evaporated and theresidue purified by column chromatography (25% ethyl acetate in hexane)to afford the title compound as a white powder (42.8 mg, 47.3%).

(c) 10-Desacetoxy-11,12-dihydropaclitaxel-10,12(18)-diene

The product of step (b) (39 mg, 0.034 mmol) was dissolved in methanol(0.5 mL) and acetic acid (0.5 mL), and treated with acid-washed zincdust (66.4 mg, 1.020 mmol). The slurry was heated at 40° C. for 1 h,filtered and the filtrate evaporated. Chromatography of the residue with60% ethyl acetate/hexane gave the title compound as a foam (22 mg, 81%).

(c) 10-Desacetoxypaclitaxel

The product of step (c) (22 mg, 0.028 mmol) in ethyl acetate (0.7 mL)was hydrogenated at atmospheric pressure in the presence of palladium oncharcoal (10%, 14.7 mg, 0.014 mmol Pd) After 5.5 h at RT, filtration(rinsing with ethyl acetate), evaporation and chromatography (60% ethylacetate in hexane) gave the title product (15.0 mg, 68%) as a whitefoam.

Preparation 2. 7-Deoxy-7α-fluoropaclitaxel ##STR24## (a)2'-O-Benzyloxycarbonyl-7-deoxy-7α-fluoropaclitaxel

Diethylaminosulfur trifluoride (DAST, 18.7 μL, 0.141 mmol) was dissolvedin dry dichloromethane (0.5 mL), and this solution was cooled to 0° C. Asolution of 2'-O-(benzyloxycarbonyl)paclitaxel (71 mg, 0.072 mmol) indichloromethane (1 mL) was added and the resulting solution was kept at0° C. for 30 min and at room temperature for 4 h. Then, water (0.15 mL)was added to the reaction mixture in order to quench the reaction andthe resultant mixture was concentrated to leave a residue. The residuewas chromatographed on a silica gel column (being eluted with 40% ethylacetate in hexane) to yield 61 mg (Y: 85.7%) of a 1:1 mixture of thetitle compound and2'-O-benzyloxycarbonyl-8-desmethyl-7,8-cyclopropapaclitaxel.

(b) 7-Deoxy-7α-fluoropaclitaxel

The product mixture obtained in Step (a) (89 mg) was dissolved in ethylacetate (3 mL) and the mixture was stirred under slightly over oneatmospheric pressure of hydrogen in the presence of palladium oncharcoal (10% Pd, 29 mg, 0.027 mmol). After 12 h, the solvent wasremoved, and the residue was purified by silica gel chromatography(being eluted with 40% ethyl acetate in hexane) to afford 67.7 mg of thetitle compound, along with 8-desmethyl-7,8-cyclopropapaclitaxel.

The following HPLC method was used to separate the7-deoxy-7α-fluoropaclitaxel and 8-desmethyl-7,8-cyclopropapaclitaxel.

Equipment

Pump: PE Series 4

Column: Shandon Hypercarb (graphitized carbon), 7μ, 100×4.6 mm,#59864750 (information on preparative size columns may be obtained fromKeystone Scientific, Bellefonte, Pa.)

Injector: PE ISS-100

Detector: HP-1040M

Conditions

Mobile Phase: 85:15 methylene chloride: hexane Separation not lost at80:19:1 methylene chloride:hexane:isopropyl alcohol

Flow Rate: 2.5 mL/min

Detector: 254 nm

Diluent: Sample dissolved in methylene chloride

Preparation 3. 7-Deoxy-7α-fluorobaccatin III ##STR25##

To a dry flask under an inert atmosphere was added2'-O-(benzyloxycarbonyl)paclitaxel (4 g, 4 mmol) and dry toluene (80mL). The resulting slurry was stirred at ambient temperature while drytetrahydrofuran (16 mL) was added dropwise until a colorless solutionresulted. The above solution was cooled to -78° C. in a dry ice/acetonebath then treated with diethylaminosulfur trifluoride (DAST, 1.2 mL, 2.5eq.). The reaction mixture was allowed to stir for 16 h as it graduallywarmed to ambient temperature. The resulting suspension was filtered andthe filtrate (diluted with ethyl acetate (30 mL)) was washed withsaturated aqueous sodium bicarbonate followed by brine. The organicfraction was dried (MgSO₄) and concentrated to give a crude product as awhite foam. The crude material was partially purified by silica gelcolumn chromatography (eluted with 10% CH₃ CN in CH₂ Cl₂) to afford 1.45g of a mixture of 2'-O-(benzyloxycarbonyl)-7-deoxy-7α-fluoropaclitaxeland 2'-O-(benzyloxycarbonyl)-8-desmethyl-7,8-cyclopropapaclitaxel (82:18mixture by ¹ H-NMR).

The above mixture (1.45 g) was taken up in ethyl acetate (60 mL) andtreated with palladium on carbon (300 mg). After shaking for 4 h under50 pounds per square inch (psi) of hydrogen, the reaction was vented andfiltered through a short plug of silica gel and concentrated. Thisfurnished the desired product mixture, 7-deoxy-7α-fluoropaclitaxel and8-desmethyl-7,8-cyclopropapaclitaxel, as a white foam (1.24 g, Y: 99%,90:10 mixture by ¹ H-NMR). This mixture was taken up in dry methylenechloride (30 mL) and treated with tetrabutylammoniumborohydride (745 mg,2.9 mmol, 2 eq) and allowed to stir for 6 h. The reaction was thenquenched with acetic acid (1 mL), diluted with additional methylenechloride (30 mL) and washed with saturated aqueous sodium bicarbonatesolution. The organic fraction was dried (MgSO₄) and concentrated. Thecrude, substituted taxane core mixture was partially purified by silicagel column chromatography (eluted with 10% CH₃ CN in CH₂ Cl₂) to give a90:10 mixture (as determined by ¹ H-NMR) of 7-deoxy-7-α-fluorobaccatinIII and 8-desmethyl-7,8-cyclopropabaccatin III (510 mg, 60%) as a whitefoam. The resulting foam was crystallized from hot isopropanol to give7-deoxy-7α-fluorobaccatin III (as small white needles (Y: 410 mg); m.p.234°-236° C. (decomposition).

Preparation 4. 10-Desacetoxy-7-deoxy-7α-fluoropaclitaxel ##STR26## (a)2'-O-Benzyloxycarbonyl-10-desacetoxypaclitaxel

10-Desacetoxypaclitaxel (27 mg, 0.034 mmol) in dichloromethane (1 mL)was treated with benzyl chloroformate (0.0146 mL, 0.102 mmol), followedby diisopropylethylamine (0.0177 mL, 0.102 mmol). The reaction mixturewas stirred at 0° C. for 45 min, and at rt for 12 h. Evaporation of thesolvent and silica gel chromatography (being eluted with 40% ethylacetate in hexane) gave 25.5 mg (Y: 81%) of the title compound as afoam.

(b) 10-Desacetoxy-7-deoxy-7α-fluoropaclitaxel

The product obtained in Step (a) (25.5 mg, 0.028 mmol) indichloromethane (0.8 mL) at 0° C. was treated with DAST (0.0071 mL,0.055 mmol). After 45 min at 0° C., the reaction was allowed to proceedfor 5 h at rt. Evaporation of the solvent and chromatography gave2'-O-benzyloxycarbonyl-7-deoxy-7α-fluoropaclitaxel as a crude foam. Thiscompound was dissolved in ethyl acetate (1 mL) and was stirred underslightly over one atmosphere of hydrogen in the presence of palladium oncharcoal (10%, 8.9 mg) for 12 h at rt. The catalyst was removed byfiltration and silica gel chromatography of the product gave 10 mg (Y:40% over two steps) of the title product as a foam.

Preparation 5. 10-Deacetyl-7-deoxy-7α-fluoropaclitaxel ##STR27##

A solution of2',10-O-bis(2,2,2-trichloroethoxycarbonyl)-10-deacetylpaclitaxel (120mg, 0.103 mmol) in dichloromethane (2 mL) was cooled at 0° C. andtreated with DAST (0.0266 mL, 0.207 mmol). The solution was stirred at0° C. for 30 min and at rt for 4 h. The reaction was quenched by addingwater (0.05 mL). The reaction mixture was concentrated and the residuewas purified by silica gel chromatography (being eluted with 30% ethylacetate in hexane) to afford 81 mg (Y: 68%) of2',10-O-bis(2,2,2-trichloroethoxycarbonyl)-7-deoxy-7α-fluoropaclitaxelas a foam. This compound (63 mg, 0.054 mmol) was dissolved in methanol(0.5 mL) and acetic acid (0.5 mL) and treated with zinc dust (104 mg,1.62 mmol) for 90 min at 45° C. The reaction mixture was filtered andthe filtrate was concentrated. Silica gel chromatography (being elutedwith 40% hexane in 60% ethyl acetate) of the residue afforded 38 mg (Y:86%) of the title compound as a white solid.

Preparation 6. 7-Deoxybaccatin III ##STR28## (a)7-O-[(Methylthio)thiocarbonyl]baccatin III

Baccatin III (750 mg, 1.278 mmol) was dissolved in dry tetrahydrofuran(20 mL) and imidazole (8.7 mg, 0.128 mmol) was added in one lot. Sodiumhydride (50% in mineral oil, 77 mg, 1.597 mmol) was added at roomtemperature. When gas evolution had ceased (10 min), carbon disulfide(4.6 mL) was added at once. After 3 h at room temperature, the yellowsolution was treated with methyl iodide (0.238 mL, 3.835 mmol) andstirred overnight. Work-up with ethyl acetate and water gave the titlecompound as a crude oil.

Alternate Run:

Baccatin III (394 mg, 0.672 mmol) was dissolved in tetrahydrofuran (5mL) and carbon disulfide (1 mL). To this solution was added sodiumhydride (40.3 mg, 60%, 1.009 mmol). A catalytic amount of imidazole wasalso added. The reaction mixture was stirred at room temperature for 1.5h. and then methyl iodide (122.8 μL, 2.016 mmol) was added. After 40min, the solvent was removed in vacuo, and the residue waschromatographed on silica gel (eluted with 20%-50%-60% ethyl acetate inhexanes) to afford the title product (260 mg, Y: 57.2%) together with7-epi baccatin (98.5 mg, 25%).

(b) 7-O-[(Methylthio)thiocarbonyl]-13-O-triethylsilylbaccatin III

The product of step (a) as a crude oil was dissolved in drydimethylformamide (5 mL) and treated with imidazole (870 mg, 12.78 mmol)and triethylsilyl chloride (2.10 mL, 12.78 mmol) at room temperature for15 h. Addition of water was followed by extraction into ethyl acetate.The organic layer was washed extensively with water, and then dried.Silica gel flash chromatography (being eluted with 20% ethyl acetate inhexanes) gave the title compound as a glassy solid (Y: 209 mg, 20% yieldover two steps).

Alternate Run:

The product of step (a) (193.4 mg, 0.286 mmol) was dissolved in drydimethylformamide (2.86 mL). To this solution was added imidazole (77.9mg, 1.14 mmol), followed by triethylsilyl chloride (192 μL, 1.14 mmol).The reaction mixture was stirred overnight at room temperature. After 12h, the reaction mixture was diluted with ethyl acetate (150 mL). Theorganic layer was washed with water (3×10 mL) and brine (1×10 mL),dried, and concentrated in vacuo. The residue was chromatographed onsilica gel (eluted with 20% Ethyl acetate in hexanes) to afford thetitle product (163 mg, Y: 72.0%).

(c) 7-Deoxy-13-O-triethylsilylbaccatin III

The product of step (b) (182 mg, 0.230 mmol) in dry benzene (5 mL) washeated to 80° C. in the presence of tributyltin hydride (0.310 mL, 1.150mmol) and 2,2'-azobisisobutyronitrile (AIBN, 10 mg). After 3 h thesolution was allowed to cool, and the solvent evaporated in vacuo.Silica gel chromatography of the residue (being eluted with 20% ethylacetate in hexane) gave the title compound as an oil.

(d) 7-Deoxybaccatin III

The product of step (c) was dissolved in tetrahydrofuran (5 mL) andtreated with tetrabutylammonium fluoride (1M in tetrahydrofuran, 0.50mL, 0.50 mmol) for 2 h at room temperature. Dilution with ethyl acetateand washing with water and brine, followed by silica gel chromatography(being eluted with 1:1 ethyl acetate/hexane) gave the title compound asa white glassy solid (63 mg, Y: 58% over two steps).

Preparation 7. 10-Desacetoxybaccatin III ##STR29## (a)10-Deacetyl-10-O-(pentafluorophenoxy)thiocarbonyl-7-O-triethylsilylbaccatinIII

7-O-Triethylsilyl-10-deacetylbaccatin III (see Greene et al, J. Am.Chem. Soc., 110, p. 5917, 1988) (319 mg, 0.485 mmol) was dissolved indry tetrahydrofuran (5 mL), cooled to -40° C., and treated withn-butyllithium (1.58M in hexanes, 0.384 mL, 0.606 mmol). After 40 min atthis temperature, pentafluorophenyl chlorothionoformate (0.086 mL, 0.536mmol) was added neat by syringe. The reaction mixture was stirred at-20° C. for 90 min, quenched with saturated ammonium chloride solution,and extracted with ethyl acetate. The ethyl acetate layer was dried andconcentrated. The residue was purified by silica gel chromatography(being eluted with 40% ethyl acetate in hexane) to afford the titlecompound as a foam (320 mg, Y: 74%).

(b) 10-Desacetoxy-7-O-triethylsilylbacctain III

The product of step (a) (119 mg, 0.135 mmol) was dissolved in drytoluene (3 mL) and treated with AIBN (2 mg). The solution was degassedwith dry nitrogen, then tributyltin hydride (0.055 mL, 0.202 mmol) wasadded. Subsequently, the solution was heated at 90° C. for 1 h. Thesolvent was then evaporated and silica gel chromatography of the residue(being eluted with 40% ethyl acetate in hexane) gave the title compound(87 mg, Y: 99%) as a colorless foam.

(c) 10-Desacetoxybaccatin III

The product of step (b) (120 mg, 0.187 mmol) was dissolved inacetonitrile (3.5 mL) and the solution was cooled to -10° C.Concentrated HCl (36%, 0.060 mL) was added, and the solution was stirredfor 30 min. The mixture was diluted with ethyl acetate (75 mL), andwashed with saturated aqueous sodium bicarbonate and brine, then driedand concentrated. The residue was purified by flash silicachromatography (being eluted with 70% ethyl acetate in hexane) to afford10-deacetyloxybaccatin III as a foam (75 mg, Y: 76%).

Preparation 8. 10-Desacetoxy-7-deoxybaccatin III ##STR30## (a)7-O-[(Methylthio)thiocarbonyl]-10-desacetoxybaccatin III

10-Desacetoxybaccatin III (75 mg, 0.142 mmol) was dissolved in drytetrahydrofuran (2 mL) and carbon disulfide (0.5 mL). Sodium hydride(60% in mineral oil, 8.5 mg, 0.213 mmol) was then added, and the mixturewas stirred at room temperature for 2 h. Iodomethane (0.026 mL, 0.426mmol) was added, and the reaction was allowed to proceed overnight. Thesolvent was then removed and the residue was purified by silica gelchromatography (being eluted with 50-70% ethyl acetate in hexane) togive the title compound as a foam (46.4 mg, Y: 53%).

(b) 10-desacetoxy-7-deoxy-baccatin III

The product of step (a) (36 mg, 0.058 mmol) was refluxed in benzene (1mL) in the presence of AIBN (2 mg) and tributyltin hydride (0.079 mL,0.290 mmol) under an argon atmosphere for 3 h. Concentration of thereaction mixture and flash silica gel chromatography of the residue(being eluted with 40% ethyl acetate in hexanes) followed by HPLC (highpressure liquid chromatography) separation from other componentsafforded the title compound as a foam (16.8 mg, Y: 56%).

Alternate Run:

To a solution of7-O-[(methylthio)carbonothioyl]-13-O-triethylsilylbaccatin III (productof preparation I, step (b), 416.3 mg, 0.527 mmol) in dry toluene (10.5mL) was added catalytic amount of AIBN, and the resulting solution wasdegassed with dry N₂ for 5 min. Tributyltin hydride (708.7 uL, 2.63mmol) was the added and the reaction mixture was heated at 100° C. for 2h., after which another portion of tributyltin hydride (425.3 uL, 1.581mmol) was added. The reaction mixture was heated for 5.5 h at 100° C.,and then allowed to cool to room temperature. Silica gel chromatography(eluted with 20% ethyl acetate in hexanes) afforded7-deoxy-10-desacetoxy-13-O-(triethysilyl)baccatin III (320 mg, Y: 97%).

To a solution of the product of the above step (160 mg, 0.255 mmol) indry tetrahydrofuran (2 mL) at room temperature was addedtetrabutylammonium fluoride (766 uL, 1M, 0.766 mmol). The reactionmixture was stirred for 1 h at room temperature. The solvent was removedand the residue was chromatographed on silica gel (eluted with 50-70%ethyl acetate in hexanes) to afford the desired title product (115 mg,Y: 87.9%).

Preparation 9. (3R,4S)-1-t-Butoxycarbonyl-4-phenyl-3-triethylsilyloxy-2-azetidinone##STR31##

To a stirred solution of(3R,4S)-4-phenyl-3-triethylsilyloxy-2-azetidinone (2.200 g, 7.92 mmol)in dry tetrahydrofuran (25 mL) was added N,N-diisopropylethylamine (1.65mL. 9.510 mmol, 1.2 equiv) at 0° C. under an argon atmosphere. Thesolution was stirred for 5 min followed by the addition of di-t-butyldicarbonate (2.080 g, 9.510 mmol, 1.2 equiv) and 4-dimethylaminopyridine(193.6 mg, 1.581 mmol, 0.20 equiv). The reaction mixture was stirred at0° C. for 60 min., then diluted with ethyl acetate (25 mL). Theresulting solution was washed with brine, 10% NaHCO₃, 10% HCl solution,dried (MgSO₄), and concentrated to give a crude compound (oil). Thecompound was further purified by silica gel flash chromatography (beingeluted with 15% ethyl acetate in hexanes) to afford the title compoundas a white solid (2.4 g, Y: 83%).

Preparation 10. (±)-cis-3-Acetyloxy-4-phenylazetidin-2-one ##STR32##

(a) To a 1 L, 3-necked round bottom flask equipped with a thermometer,magnetic stirrer and dropping funnel was added hydrobenzamide (30.00 g,100.5 mmol) and ethyl acetate (150 mL). With stirring and under ablanket of argon, the reaction mixture was cooled to 5° C. andtriethylamine (16.8 mL, 121 mmol) was added. A solution of acetoxyacetylchloride (12.4 mL, 116 mmol) in ethyl acetate (300 mL) was then addeddropwise over a 90 min period. After 16 h at this temperature, thereaction mixture was allowed to warm to 20° C. (1.5 h) and transferredto a separatory funnel. The organic layer was washed successively withaqueous NH₄ Cl (sat) (150 mL, 100 mL), aqueous NaHCO₃ (saturated) (120mL) and brine (120 mL). For purposes of characterization, the titlecompound can be isolated at this stage by drying the organic phase overMgSO₄, filtering, and removing the solvent in vacuo. This provided(±)-cis-3-acetyloxy-1-[(phenyl)(benzylidenimino)methyl]-4-phenylazetidin-2-onein quantitative crude yield as a red glass.

(b) A solution of the compound obtained in part (a) in ethyl acetate(500 mL) was carefully transferred, under a stream of argon, to a 2.0 LParr flask containing 10% palladium on activated charcoal (6.00 g). Thismixture was treated with hydrogen (4 atm) for 20 h whereupon thecatalyst was removed by filtration through a pad of Celite. The filtercake was slurried in ethyl acetate (200 mL), stirred (10 min) andfiltered. The filter cake was rinsed with ethyl acetate (100 mL) and thefiltrates combined. The organic layer was washed with 10% HCl (300 mL)and both layers filtered through a sintered glass funnel to remove thewhite precipitate (dibenzylamine HCl) which was rinsed with ethylacetate (100 mL). The phases were separated and the organic layer waswashed with another portion of 10% HCl (200 mL). The combined 10% HClwashes were re-extracted with ethyl acetate (200 mL) and the combinedorganic layers were washed with aqueous NaHCO₃ (saturated) (300 mL) andbrine (250 mL). The organic layer was dried over MgSO₄, filtered andconcentrated in vacuo to a final volume of 75 mL. This mixture wascooled to 4° C. and the precipitated product isolated by filtration. Thefilter cake was washed with hexane (200 mL) to provide 16.12 g (78.1%overall yield from hydrobenzamide) of the title compound as whiteneedles.

mp=150°-151° C.

Preparation 11.(±)-cis-3-Triethylsilyloxy-4-(2-furyl)-N-t-butoxycarbonylazetidin-2-one##STR33##

(a) The procedure described in Preparation 10, part (a), was followedexcept that hydrofuramide [i.e. 2-furyl-CH--(N═CH-2-furyl)₂ ] was usedinstead of hydrobenzamide and the reaction was performed on 18.6 mmol(vs 100 mmol) scale. Thus, hydrofuramide (5.00 g, 18.6 mmol),triethylamine (3.11 mL, 22.3 mmol) and acetoxyacetyl chloride (2.30 mL,21.4 mmol) gave 6.192 g (Y: 90.4%) of(±)-cis-3-acetyloxy-1-[(2-furyl)(2-furylmethylenimino)methyl]-4-(2-furyl)azetidin-2-oneas a pale red syrup.

(b) The procedure described in Preparation 10, part (b), was followedexcept that the product was isolated by preparative TLC and the reactionwas performed on the 2.7 mmol scale based on the original amount ofhydrofuramide. Thus, the crude product obtained in part (a) above wasre-dissolved in ethyl acetate (50 mL) and added to 10% palladium onactivated charcoal (150 mg). Purification of the crude solid bypreparative TLC (2 mm silica gel, eluted with 1:1 ethyl acetate/hexane)gave 386 mg (65.8% corrected overall yield from hydrofuramide)(±)-cis-3-(acetyloxy)-4-(2-furyl)azetidin-2-one as a yellow solid. Thiswas recrystallized from ethyl acetate/hexane.

mp=118°-119° C.

(c) The compound obtained in part (b) above (3.78 g, 19.4 mmol) in 60 mLof methanol was stirred with K₂ CO₃ (20 mg, 0.14 mmol) for 90 min andthe solution neutralized with Dowex 50W-X8 and filtered. The filtratewas concentrated and the residue dissolved in 80 mL of anhydrous THF andstirred at 0° C. with imidazole (1.44 g, 21.2 mmol) and TESCl (3.4 mL,20.2 mmol) for 30 min. The solution was diluted with ethyl acetate andwashed with brine, dried over MgSO₄ and concentrated. The residue waschromatographed over silica gel (eluted with 3:1 hexane/ethyl acetate)to give 4.47 g (Y: 86%) of (±)-cis-3-triethylsilyloxy-4-(2-furyl)-azetidin-2-one as a colorless oil.

(d) The product of part (c) (2.05 g, 7.7 mmol) in 30 mL ofdichloromethane was stirred at 0° C. with diisopropylethyl amine (1.5mL, 8.6 mmol) and di-t-butyl dicarbonate (2.0 g, 9.2 mmol) in additionto a catalytic amount of dimethylaminopyridine (DMAP). The solution wasdiluted with dichloromethane and washed with brine, dried over MgSO₄ andconcentrated. The residue was chromatographed over silica gel (elutedwith 8:1 hexane/ethyl acetate) to give 2.0 (Y: 70%) of the titlecompound as a waxy solid.

The racemic mixture obtained in part (b) may be used as substrate forenzymatic hydrolysis using a lipase such as PS-30 from Pseudomonas sp.(Amano International Co.) to give(3R,4R)-3-hydroxy-4-(2-furyl)-azetidin-2-one. The method of enzymaticresolution using the lipase PD-30 and other enzymes is disclosed in ourco-pending application U.S. Ser. No. 092,170, filed Jul. 14, 1993 whichis hereby incorporated by reference in its entirety.

The procedure in parts (c) and (d) was followed using(3R,4R)-3-hydroxy-4-(2-furyl)-azetidin-2-one to provide(3R,4R)-N-(t-butoxycarbonyl)-3-triethylsilyoxy-4-(2-furyl)azetidine-2-one.

Preparation 12. (±)-cis-3-Triethylsilyloxy-4-(2-thienyl)-N-t-butoxycarbonylazetidin-2-one##STR34##

(a) The procedure described in Preparation 10, step (a) was followedexcept that hydrothienamide [i.e. 2-thienyl-CH--(N═CH-2-thienyl)₂ ] wasused instead of hydrobenzamide. Thus, hydrothienamide (30 g, 94.7 mmol),thiethylamine (15.84 mL, 114 mmol) and acetoxyacetyl chloride (11.6 mL,108 mmol) provided(±)-cis-3-acetyloxy-1-[(2-thienyl)(2-trienylmethylenimino)methyl]-4-(2-thienyl)azetidin-2-oneas viscous oil.

(b) A 70% aqueous solution of acetic acid (0.35 mL glacial acetic acidand 0.15 mL water) was added in one portion to a stirred solution of theproduct obtained in part (a) (0.431 g, 1.03 mmol) in dichloromethane(2.93 ml) at 25° C. The reaction mixture was brought to reflux andstirred for 2.5 h. The reaction was diluted with 50 mL dichloromethaneand then washed with two 75 mL portions of saturated aqueous sodiumbicarbonate and then one 50 mL portion of saturated brine. The organicextract was concentrated in vacuo to a brown oil, dissolved in a minimalamount of dichloromethane, and then placed on a silica gel columnmeasuring 4" by 0.5". Elution using a gradient of 10 through 60% EtOAcin hexane provided less polar sideproducts and then(±)-cis-3-acetyloxy-4-(2-thienyl)azetidin-2-one (0.154 g, Y: 75%) as awhite solid.

(c) A solution of the product obtained in part (b) (2.5 g, 11.8 mmol)was dissolved in methanol (10 mL) and treated with saturated aqueoussodium bicarbonate (10 mL) and the resulting slurry was allowed to stirat ambient temperature for 3 h. The reaction was then diluted with ethylacetate (20 mL) and washed with water (15 mL). The aqueous fraction wasback extracted several times with ethyl acetate and the combined organicfractions were dried (MgSO₄) and concentrated to give a yellow solid (Y:1.7 g). The crude material was dissolved in dry tetrahydrofuran (20 mL)and the solution was cooled to 5° C. in an ice/water bath. Imidazole(752 mg, 1.1 eq) was then added. After stirring 5 min,triethylchlorosilane (1.85 mL, 1.1 eq) was added dropwise. The resultingsuspension was allowed to stir for 3 h at that temperature; then thesolids were removed by filtration. The organic fraction was washed withwater (2×20 mL) then dried (MgSO₄) and concentrated. The crude productwas purified by silica gel column chromatography (eluted withhexanes/ethyl acetate 7:3) to give(±)-cis-3-triethylsilyloxy-4-(2-thienyl)-azetidin-2-one as a colorlesssolid (1.5 g, Y: 45%). m.p. 70°-71° C.

Alternate Run:

The product obtained in part (b) (2.0 g, 9.37 mmol) in 40 mL of methanolwas stirred with K₂ CO₃ (60 mg, 0.43 mmol) for 30 min and the solutionneutralized with Dowex 50W-X8 and filtered. The filtrate wasconcentrated and the residue dissolved in 50 mL of anhydrous THF andstirred at 0° C. with imidazole (0.85 g, 11.3 mmol) and TESCl (1.9 mL,12.5 mmol) for 30 min. The solution was diluted with ethyl acetate andwashed with brine, dried over MgSO₄ and concentrated. The residue waschromatographed over silica gel (eluted with 3:1 hexane/ethyl acetate)to give 2.13 g (Y: 86%) of the title product as a colorless oil.

(d) A solution of the product obtained in part (c) (425.7 mg, 1.48 mmol)was dissolved in dichloromethane (10 mL) and cooled to 5° C. in anice/water bath. The reaction was treated with a catalytic amount of DMAPfollowed by diisopropylethylamine (TESCl, 0.25 mL, 1.0 eq) then bydi-t-butyl dicarbonate (388.4 mg, 1.2 eq). After stirring 2 h at thattemperature the reaction was quenched with saturated aqueous sodiumbicarbonate (5 mL) and the organic fraction was washed with water (5 mL)then dried (MgSO₄), passed through a short plug of silica gel andconcentrated to give the desired product as a colorless oil (525.3 mg,Y: 93%).

Prepartion 13. (3R,4R)-3-Triethylsilyloxy-4-(2-furyl)-N-n-butyloxycarbonylazetidin-2-one##STR35##

(3R,4R)-3-Triethylsilyloxy-4-(2-furyl)azetidin-2-one (0.58 g, 2.17 mmol)in 30 mL of dichloromethane was stirred with diisopropylethyl amine (0.4mL, 2.30 mmol) and butylchloroformate (0.3 mL, 2.36 mmol) in addition toa catalytic amount of DMAP. The solution was stirred for 1 h and dilutedwith dichloromethane and washed with brine, dried over MgSO₄ andconcentrated. The residue was chromatographed over silica gel (elutedwith 3:1 hexane/ethyl acetate) to give 523 mg of product (Y: 65%);IR(KBr) 1820, 1734, 1318, 1018, 734 cm⁻¹ ; ¹ H-NMR (CDCl₃, 300 MHz) δ7.38 (m, 1H), 6.35 (m, 2H), 5.09 (ABq, J=15.5, 5.6 Hz, 2H), 4.14 (m,2H), 1.56 (m, 2H), 1.28 (s, 2H), 0.87 (t, J=8.7 Hz, 3H), 0.82 (t, J=7.9,9H), 0.50 (m, 6H); ¹³ C-NMR (CDCl₃, 75.5 Hz) δ 165.4, 149.1, 147.6,142.9, 110.5, 109.9, 77.7, 66.6, 55.9, 30.5, 18.8, 13.6, 6.3, 4.3; DCIMSM+H calcd for C₁₈ H₂₉ NO₅ Si: 368, Found: 368.

Preparation 14.(3R,4R)-3-Triethylsilyloxy-4-(2-furyl)-N-isopropyloxycarbonylazetidin-2-on##STR36##

(3R, 4R)-3-Triethylsilyloxy-4-(2-furyl)azetidin-2-one (0.51 g, 1.91mmol) in 25 mL of dichloromethane was stirred with diisopropylethylamine (0.78 mL, 4.4 mmol) and i-propylchloroformate (4.0 mL, 1.0M intoluene, 4.0 mmol) in addition to a catalytic amount of DMAP. Thesolution was stirred for 1 h and diluted with dichloromethane and washedwith brine, dried over MgSO₄ and concentrated. The residue waschromatographed over silica gel (eluted with 5:1 hexane/ethyl acetate)to give 649 mg of the title product (Y: 96%); IR(KBr) 1822, 1812, 1716,1374, 1314, 1186, 1018, 1004, 746 cm⁻¹ ; ¹ H-NMR (CDCl₃, 300 MHz) δ 7.39(m, 1H), 6.35 (m, 2H), 5.08 (ABq, J=15.6, 5.6 Hz, 2H), 4.96 (d, J=10.0Hz, 1H), 1.25 (d, J=6.3 Hz, 3H), 1.17 (d, J=6.3 Hz, 3H)), 0.83 (t,J=7.8, 9H), 0.50 (m, 6H); ¹³ C-NMR (CDCl₃, 75.5 Hz) δ 165.5, 148.6,147.8, 142.9, 110.5, 109.9, 77.6, 71.1, 55.9, 21.7, 21.6, 6.3, 4.4;DCIMS M+H calcd for C₁₇ H₂₈ NO₅ Si: 354, Found: 354.

Preparation 15.(±)-cis-3-Triethylsilyloxy-4-isobutenyl-N-t-butoxycarbonylazetidin-2-one(a) N-4 -methoxy-N-(3-methyl-2-butenyl)benzenamine ##STR37##

A solution of p-anisidine (5.7 g, 46.3 mmol) was dissolved indiethylether (100 mL) and was treated with a catalytic amount ofp-toluensulfonic acid (10 mg). To this was added 3-methyl-2-butenal(2.67 mL, 50.9 mmol) in one portion and the reaction was allowed to stirat ambient temperature for 16 h. The solvent was then evaporated on arotary evaporator at 0.5 torr to furnish the desired imine (8.7 g, 100%)as a brown oil; ¹ H NMR 300 MHz, CDCl₃): δ 8.38 (d, 1H, J=9.5 Hz), 7.11(dd, 2H, J=2.2, 6.7 Hz), 6.88 (dd, 2H, J=2.2, 6.7 Hz), 6.22-6.18 (m,1H), 3.81 (s, 3H), 2.01 (s, 3H), 1.95 (s, 3H).

(b) (±)-cis-N-(4-methoxyphenyl)-3-acetyloxy-4-isobutenylazetidin-2-one##STR38##

A solution of acetoxyacetyl chloride (6.9 g, 50.5 mmol) was dissolved inethyl acetate (100 mL) and cooled to -30° C. under an inert atmosphere.To this solution was added triethylamine (7.0 mL, 50.5 mmol) over a 5min period. The resulting white slurry was then treated with an ethylacetate solution of N-4-methoxy-N-(3-methyl-2-butenyl)benzenamine (8.7g, 40 mL) dropwise over a 20 min period. The resulting green-brownslurry was then gradually allowed to warm to ambient temperature over a4 h period. The slurry was then filtered through a pad of celite and thefiltrate was washed with water then brine. The organic fraction wasdried (MgSO₄) and concentrated to give a brown oil. The crude productwas purified by careful silica gel chromatography (eluted withhexanes/ethyl acetate 8:2) to furnish an orange oil which solidified onstanding. This was recrystallized from dichloromethane/hexanes tofurnish the desired product as a pale yellow solid (4.4 g, 32%); ¹ H NMR(300 MHz, CDCl₃): δ 7.32 (d, 2H, J=9.1 Hz), 6.86 (d, 2H, J=9.1 Hz), 5.59(dd, 1H, J=3.0, 7.8 Hz), 5.14-5.10 (m, 1H), 4.96 (dd, 1H, J=4.8, 9.3Hz), 3.77 (s, 3H), 2.11 (s, 3H,), 1.81 (s, 3H), 1.78 (s, 3H).

(c) (±)-cis-3-Acetyloxy-4-isobutenylazetidin-2-one ##STR39##

A solution of the(±)-cis-N-(4-methoxyphenyl)-3-acetyloxy-4-isobutenylazetidin-2-one (4.88g, 16.2 mmol) was dissolved in acetonitrile (50 mL) and cooled to 0°-5°C. in an ice bath. To this was added a cold solution of ceric ammoniumnitrate (26.6 g, 48.6 mmol, 50 mL) in one portion. The deep red reactionwas allowed to stir for 10 min and during that time the color graduallylightened to orange. The cold solution was transferred to a separatoryfunnel, diluted with water, and extracted with ethyl acetate. Theorganic fraction was washed with several portions of 10% aqueous sodiumsulfite, followed by saturated aqueous sodium bicarbonate. The organicfraction was dried (MgSO₄) and concentrated to give the desired product(2.71 g, 91%) as a yellow-orange solid that was used directly in thenext step; ¹ H NMR (300 MHz, CDCl₃): δ 6.11 (bs, 1H), 5.73 (dd, 1H,J=2.2, 4.7 Hz), 5.12-5.08 (m, 1H), 4.63 (dd, 1H, 4.7, 9.1 Hz), 2.09 (s,3H), 1.75 (s, 3H), 1.67 (s, 3H).

(d) (±)-cis-3-Triethylsilyloxy-4-isobutenylazetidin-2-one ##STR40##

(±)-cis-3-Acetyloxy-4-isobutenylazetidin-2-one (1.47 g, 8.0 mmol) wasdissolved in methanol (15 mL) and was stirred with K₂ CO₃ (110.5 mg, 0.8mmol) for 3 h at ambient temperature. The solution was then neutralizedwith Dowex 50W-X8 resin and then filtered. The filtrate was concentratedand the crude solid was dissolved in THF (25 mL) and cooled to 5° C. inan ice bath. Imidazole (544.0 mg, 8.0 mmol) was added and oncedissolved, triethylsilyl chloride (1.34 mL, 8.0 mmol) was added dropwisevia syringe. The resulting slurry was allowed to warm to ambienttemperature and stir overnight. The solution was filtered and thefiltrate was washed with water, then brine. The organic fraction wasdried (MgSO₄) and concentrated. The crude solid was purified by silicagel chromatography (eluted with hexanes/ethyl acetate 3:1) to furnishthe desired product (612 mg, 30%) as a pale yellow solid; ¹ H NMR (300MHz, CDCl₃): δ 5.87 (bs, 1H), 5.31-5.26 (m, 1H), 4.90 (dd, 1H, J=2.2,4.7 Hz), 4.42 (dd, 1H, J=4.7, 9.3 Hz), 1.74 (s, 3H), 1.28 (s, 3H),0.98-0.91 (m, 9H), 0.71-0.55 (m, 6H).

(e)(±)-cis-3-Triethylsilyloxy-4-isobutenyl-N-t-butoxycarbonylazetidin-2-one##STR41##

(±)-cis-3-Triethylsilyloxy-4-isobutenylazetidin-2-one (1.01 g, 3.95mmol) was dissolved in dichloromethane (20 mL) and was treated withdiisopropylethylamine (0.68 mL, 3.95 mmol) and a catalytic amount ofdimethylaminopyridine. To this solution was added di-t-butyl dicarbonate(1.02 g, 4.68 mmol) and the solution was allowed to stir for 24 h atambient temperature. The solution was then diluted with additionaldichloromethane and washed with water then brine. The organic fractionwas dried (MgSO₄) and concentrated. The residue was purified by silicagel chromatography (eluted with hexanes/ethyl acetate 8:2) to give thedesired product (1.26 g, 90%) as a colorless oil; ¹ HNMR (300 MHz,CDCl₃): δ 5.24 (d, 1H, J=9.6 Hz), 4.86 (d, 1H, J=5.7 Hz), 4.72 (dd, 1H,J=6.0, 9.9 Hz), 1.78 (d, 3H, J=1.1 Hz), 1.75 (d, 3H, J=1.1 Hz), 1.47 (s,9H), 0.96-0.91 (m, 9H), 0.64-0.55 (m, 6H).

The procedure described above in Preparations 9, 11(d), 12(d), 13, 14,and 15(e) may be adapted to the preparation of other N-substitutedazetidinones useful in the preparation of compounds of the invention.

Examples of such azetidinones are listed in the following table; P belowis a hydroxy protecting group such as triethyl silyl, triisopropylsilyland ethoxyethyl.

    ______________________________________                                         ##STR42##                                                                    L            R.sup.4 (O).sub.p                                                                         R.sup.5                                              ______________________________________                                        Cl           Ph          4-CH.sub.3 OPh                                                                3,4-diCH.sub.3 OPh                                                            Ph                                                                            4-FPh                                                                         4-CF.sub.3 Ph                                                                 2-furanyl-                                                                    2-thienyl-                                                                    PhCHCH                                                                        2-furanyl-CHCH                                                                (CH.sub.3).sub.2 CHCH.sub.2                                                   C.sub.6 H.sub.11 CH.sub.2                                                     (CH.sub.3).sub.2 CH                                                           PhCH.sub.2 CH.sub.2                                                           C.sub.6 H.sub.11 CH.sub.2 CH.sub.2                                            CH.sub.3 CH.sub.2 CH.sub.2                                                    4-ClPh                                                                        2-FPh                                                                         3-FPh                                                                         4-CH.sub.3 Ph                                                                 (CH.sub.3).sub.2 CCH                                 Cl           4-CH.sub.3 OPh                                                                            3,4-diCH.sub.3 OPh                                                            4-CF.sub.3 Ph                                                                 2-furanyl-                                                                    PhCHCH                                                                        (CH.sub.3).sub.2 CHCH.sub.2                                                   C.sub.6 H.sub.11 CH.sub.2                                                     PhCH.sub.2 CH.sub.2                                  (CH.sub.3).sub.3 COCO.sub.2                                                                (CH.sub.3).sub.3 CO                                                                       4-CH.sub.3 OPh                                                                4-FPh                                                                         4-CF.sub.3 Ph                                                                 PhCHCH                                                                        (CH.sub.3).sub.2 CH                                                           PhCH.sub.2 CH.sub.2                                                           C.sub.6 H.sub.11 CH.sub.2 CH.sub.2                                            CH.sub.3 CH.sub.2 CH.sub.2                           Cl           CH.sub.3    4-CH.sub.3 OPh                                                                Ph                                                                            4-FPh                                                                         2-furanyl-                                                                    2-furanyl-CHCH                                                                PhCH.sub.2 CH.sub.2                                                           C.sub.6 H.sub.11 CH.sub.2 CH.sub.2                                            CH.sub.3 CH.sub.2 CH.sub.2                           ______________________________________                                    

Preparation 16. 10-deoxytaxotere ##STR43##

10-Desacetoxy-7-O-triethylsilylbaccatin III (100 mg, 0.156 mmol) wasplaced in a flask under argon and dissolved in dry tetrahydrofuran (1.5mL). Upon cooling to -40° C., n-butyllithium (1.45M in hexanes, 0.119mL, 0.170 mmol) was added dropwise, followed by(3R,4S)-1-tert-butoxycarbonyl-4-phenyl-3-triethylsilyloxy-2-azetidinone(94.2 mg, 0.25 mmol) in tetrahydrofuran (0.5 mL) over a period of 2 min.The mixture was immediately warmed to 0° C. and stirred for 45 minbefore being quenched with saturated ammonium chloride (3 mL). Themixture was extracted with ethyl acetate, dried, and concentrated.Silica gel chromatography (eluted with 30% ethyl acetate in hexane)afforded 10-deoxy-2',7-bis-O-(triethylsilyl)taxotere as a foam (125 mg,Y: 76%). This compound (100 mg, 0.098 mmol) was immediately dissolved inacetonitrile (2 mL) at -5° C. and treated with hydrochloric acid (0.037mL, 36%, 12M). The mixture was stirred for 2 h at -5° C., then quenchedwith aqueous bicarbonate, extracted with ethyl acetate, and dried.Evaporation of the solvent was followed by silica gel chromatography(eluted with 75% ethyl acetate in hexane) to afford the title compoundas a foam (80.5 mg, Y: 80%).

The general procedure provided in Preparation 16 may be adapted to thepreparation of other compounds of formula (Ia) by starting with theappropriate baccatin III component and the azetidinone component;examples of other compounds of formula (Ia) are listed in the followingtable. It will be understood that even though the compounds below areshown with free hydroxy groups, with the judicious selection of thevarious hydroxy protecting groups, any one of the protecting groups atthe 2'-, 7- or 10-position may be selectively removed without affectingother protecting groups present.

    ______________________________________                                         ##STR44##                                                                    R.sup.2'                                                                           R.sup.2a                                                                             R.sup.3a                                                                             R.sup.4 (O).sub.p                                                                          R.sup.5                                       ______________________________________                                        H    OH     AcO    Ph           4-CH.sub.3 OPh                                                                3,4-diCH.sub.3 OPh                                                            Ph                                                                            4-FPh                                                                         4-CF.sub.3 Ph                                                                 2-furanyl-                                                                    2-thienyl-                                                                    PhCHCH                                                                        2-furanyl-CHCH                                                                (CH.sub.3).sub.2 CHCH.sub.2                                                   C.sub.6 H.sub.11 CH.sub.2                                                     (CH.sub.3).sub.2 CH                                                           PhCH.sub.2 CH.sub.2                                                           C.sub.6 H.sub.11 CH.sub.2 CH.sub.2                                            CH.sub.3 CH.sub.2 CH.sub.2                                                    4-ClPh                                                                        2-FPh                                                                         3-FPh                                                                         4-CH.sub.3 Ph                                 H    OH     OH     (CH.sub.3).sub.3 CO                                                                        4-CH.sub.3 OPh                                                                Ph                                                                            4-FPh                                                                         4-CF.sub.3 Ph                                                                 2-furanyl-                                                                    2-thienyl-                                                                    PhCHCH                                                                        C.sub.6 H.sub.11 CH.sub.2                                                     (CH.sub.3).sub.2 CH                                                           PhCH.sub.2 CH.sub.2                                OH     H      Ph           4-CH.sub.3 OPh                                                                3,4-diCH.sub.3 OPh                                                            4-FPh                                                                         4-CF.sub.3 Ph                                                                 2-furanyl-                                                                    2-thienyl-                                                                    PhCHCH                                                                        2-furanyl-CHCH                                                                (CH.sub.3).sub.2 CHCH.sub.2                                                   C.sub.6 H.sub.11 CH.sub.2                                                     (CH.sub.3).sub.2 CH                                                           PhCH.sub.2 CH.sub.2                                                           C.sub.6 H.sub.11 CH.sub.2 CH.sub.2                                            CH.sub.3 CH.sub.2 CH.sub.2                         H      H      (CH.sub.3).sub.3 CO                                                                        4-CH.sub.3 OPh                                                                3,4-diCH.sub.3 OPh                                                            Ph                                                                            4-FPh                                                                         4-CF.sub.3 Ph                                                                 2-furanyl-                                                                    2-thienyl-                                                                    PhCHCH                                                                        2-furanyl-CHCH                                                                (CH.sub.3).sub.2 CHCH.sub.2                                                   C.sub.6 H.sub.11 CH.sub.2                                                     (CH.sub.3).sub.2 CH                                                           PhCH.sub.2 CH.sub.2                                                           C.sub.6 H.sub.11 CH.sub.2 CH.sub.2                                            CH.sub.3 CH.sub.2 CH.sub.2                    H    OH     AcO    2-naphthyl   Ph                                                               4-OHPh                                                                        4-CH.sub.3 OPh                                                                4-FPh                                                                         (CH.sub.3).sub.3 CO                                                           CH.sub.3                                                                      (CH.sub.3).sub.2 CH                                                           CH.sub.2 CHCH.sub.2                                                           4-ClPh                                                     F    H      AcO    (CH.sub.3).sub.3 CO                                                                        Ph                                            F    H      OH     Ph           Ph                                            H    H      AcO    Ph           4-CH.sub.3 OPh                                                                3,4-diCH.sub.3 OPh                                                            Ph                                                                            4-FPh                                                                         4-CF.sub.3 Ph                                                                 2-furanyl-                                                                    2-thienyl-                                                                    PhCHCH                                                                        2-furanyl-CHCH                                                                (CH.sub.3).sub.2 CHCH.sub.2                                                   C.sub.6 H.sub.11 CH.sub.2                                                     (CH.sub.3).sub.2 CH                                                           PhCH.sub.2 CH.sub.2                                                           C.sub.6 H.sub.11 CH.sub.2 CH.sub.2                                            CH.sub.3 CH.sub.2 CH.sub.2                    ______________________________________                                    

Preparation 17. Bis(methylthiomethyl)ether

    CH.sub.3 SCH.sub.2 OCH.sub.2 SCH.sub.3

Sodium iodide (8.23 g, 55.23 mmol) was added to a solution of1,1'-dichlorodimethyl ether (3.0 g, 26.3 mmol) in acetone (100 ml) at 0°C. and the mixture was stirred at this temperature for 20 min. Sodiumthiomethoxide (1.84 g, 5.23 mmol) was then added in four portions andthe resulting solution was stirred for an additional 1 h. Theheterogeneous solution was then filtered through a pad of celite and thefiltrate concentrated in vacuo. The residual oil was partitioned betweenethyl acetate and saturated aqueous sodium bicarbonate solution. Theaqueous layer was removed and further extracted with ethyl acetate. Thecombined organics were then treated with a 1:1 (v:v) mixture ofsaturated aqueous sodium bicarbonate and 5% aqueous sodium thiosulfatesolution. The organics were then washed with brine, dried over sodiumsulfate and concentrated in vacuo. The residual oil was purified viaflash chromatography (30:1, hexanes:ethyl acetate) to provide 1.9 g of ayellow oil which was subsequently distilled using a kugelrhor apparatus(120°-130° C., 20 mmHg) yielding 1.5 g (45%) of the title compound ascolorless oil:

¹ H NMR (300 MHz, CDCl3) δ 4.73 (4H, s), 2.15 (6H, s).

Preparation 18. Dibenzyl Methylthiomethyl Phosphate

    CH.sub.3 SCH.sub.2 OP(O)(OBu).sub.2

To a solution of bis(methylthiomethyl)ether (30 mg, 2.34 mmol) andmolecular sieves (300 mg) in THF (100 ml) at room temperature was addeddibenzyl phosphate (2.74 g, 9.85 mmol) followed by N-iodosuccinimide(608 mg, 2.71 mmol) and the solution was stirred for 4 h. The reactionmixture was then diluted with ethyl acetate and filtered through a padof celite. The filtrate was treated with a 1:1 (v:v) solution ofsaturated aqueous sodium bicarbonate and 5% aqueous sodium thiosulfate.The colorless organic extract was then washed with brine, dried oversodium sulfate and concentrated in vacuo to provide 600 mg (69%) of thetitle compound:

¹ H NMR (300 MHz, CDCl3) δ 7.35 (10H, s), 5.29 (2H, d, J=12.2 Hz), 5.08(4H, dd, J=8.0, 1.0 Hz), 4.68 (2H, s), 2.10 (3H, s).

EXAMPLES

The following examples are provided to illustrate the synthesis ofrepresentative compounds of the instant invention and are not to beconstrued as limiting the scope of the invention in any manner. Oneskilled in the art will be able to adapt these methods, without undueexperimentation, to the synthesis of compounds within the scope of thisinvention but not specifically disclosed.

Example 1 7-O-phosphonooxymethylpaclitaxel and Its Monosodium Salt (a)Preparation of 7-O-methylthiomethylpaclitaxel ##STR45##

Benzoyl peroxide (0.98 g, 4 mmol) was added to a vigorously stirredmixture of paclitaxel (0.85 g, 1 mmol) and dimethyl sulfide (0.72 mL, 8mmol) in dry acetonitrile (10 ml) at 0° C. Stirring was continued for2.5 hours at 0° C. Progress of the reaction was monitored by silica gelTLC in toluene: acetone (2:1, v/v) solvent system (R_(f) tax. =0.38,R_(f) prod. =0.64), and when formation of higher mobility products wasobserved the reaction was quenched by evaporation of solvents usingRotavapor at 30° C. A TLC analysis of the reaction mixture indicated thepresence of some quantities of unreacted paclitaxel and2',7-O-bis(methylthiomethyl)paclitaxel. Separation of the title compoundfrom the reaction mixture was achieved by flash column chromatography onSilica Gel 60 (40-63 μm) EM Science (100 mL), column diameter: 2 in.using ethyl acetate:hexane (1:1, v/v) solvent system (R_(f) prod.=0.34). The product (552 mg, 60% yield) was recovered from fractions 12to 18 (each fraction ca. 20 ml).

MS (FAB/matrix NOBA, NaI, KI): [M+H]⁺, m/z 914; [M+Na]⁺, m/z 936;[M+K]⁺, m/z 952

Elemental Analysis: C: 64.28 (calc. 64.39), H: 5.85 (calc. 6.07), N:1.46 (calc. 1.53)

UV (MeOH): λmax=226 nm, E(1%/1 cm)=150, A=0.2653

IR (KBr): 3432, 3066, 2940, 1726, 1668, 1602, 1582, 1514, 1484, 1452,1372, 1242, 1178, 1142, 1108, 1068, 1026, 990, 916, 884, 852, 802, 774,710, 608, 570, 538, 482 cm⁻¹.

¹ H-NMR (CDCl₃) δ: 1.15 (3H, s), 1.19 (3H, s), 1.73 (3H, s), 1.79 (H,s), 1.90 (3H, d), 2.09 (3H, S), 2.16 (3H, s), 2.29 (2H, d), 2.35 (3H,s), 2.77 (H, m), 3.70 (H, d), 3.83 (H, d), 4.17 (H, d), 4.26 (H, m,overlaps with H, d), 4.63 (2H, t), 4.77 (H, dd), 4.91 (H, d), 5.65 (H,d), 5.77 (H, dd), 6.16 (H, dd), 6.48 (H, s), 7.07 (H, d), 7.29-7.50(10H, m), 7.57 (H, m), 7.73 (2H, d), 8.08 (2H, d).

(b) Preparation of 7-O-dibenzylphosphonooxymethylpaclitaxel ##STR46##

A solution of N-iodosuccinimide (45 mg, 0.2 mM) and dibenzyl phosphate(55 mg, 0.2 mM) in dry tetrahydrofuran (4 mL) was added to a mixture of7-O-methylthiomethylpaclitaxel (119 mg, 0.13 mM) and powdered molecularsieves 4 Å (ca. 120 mg) in dry 1,2-dichloroethane (5 ml). The reactionmixture was stirred at room temperature for 16 hrs. Progress of thereaction was monitored by TLC in toluene:acetone (2:1, v/v) system(R_(f) prod. =0.48). Molecular sieves were removed by filtration throughCelite 545 and the filtrate was extracted with methylene chloride (100ml). The organic layer was washed with 1% solution of sodium thiosulfate(ca. 100 ml) and 0.5M sodium bicarbonate (100 ml) and with brine.Extract was filtered through Whatman Phase Separator and solvents wereevaporated. Purification on Silica Gel 60 flash column in methylenechloride:ethyl acetate (2:1, v/v) yielded7-O-dibenzylphosphonooxymethylpaclitaxel (41.5 mg).

(c) Preparation of 7-O-phosphonooxymethylpaclitaxel and Its MonosodiumSalt ##STR47##

7-O-Dibenzylphosphonooxymethylpaclitaxel (41.5 mg) was dissolved inethyl acetate (5 ml) and 10% palladium on charcoal (20 mg) was added.Hydrogenation was performed at 40 PSI (275 kPa) at room temperature for1 hour. Progress of the reaction was monitored by TLC inchloroform:methanol:water (120:45:8, v/v). Purification by preparativeTLC (20×20×0.05 cm silica gel plate in the analytical system) gave7-O-phosphonooxymethylpaclitaxel (26 mg, 75% yield).

Because decomposition of 7-O-dibenzylphosphooxymethylpaclitaxel wasobserved during silica gel purification, the hydrogenation procedure hasbeen modified. Thus, a crude extract of7-O-dibenzylphosphonooxymethylpaclitaxel was hydrogenated without anypurification. Hydrogenation of the crude extract of7-O-dibenzylphosphonooxymethylpaclitaxel was performed at 60 PSI (400kPa) for 24 hrs.

7-O-Phosphonooxymethylpaclitaxel (70 mg) was dissolved in 5 mL ofacetone - water (1:1) solution and diluted with water to 50 ml. Drysodium bicarbonate (18 mg, 1.2 eq.) was added. Acetone was evaporated atroom temperature using Rotavapor and the remaining water solution waslyophilized. Crude 7-O-phosphonooxymethylpaclitaxel monosodium salt waspurified by C18 reverse phase column chromatography inwater:acetonitrile (70:30, v/v) system. Eluate was monitored byanalytical HPLC (15 cm, Jones C18 column, 1 mL/min., l=230/270 nm) inacetonitrile: 0.05M ammonium acetate buffer (45:55, v/v), pH=7, Rt=2.09min. Fractions containing the desired product were combined,acetonitrile evaporated and the remaining aqueous solution lyophilizedto provide 7-O-phosphonooxymethylpaclitaxel monosodium salt (112 mg).

MS (FAB): [M+H]⁺, m/z 986; [M+Na]⁺, m/z 1008

UV (MeOH): λmax=230 nm, E(1%/1 cm)=248

IR (KBr): 3430, 3066, 2948, 1724, 1652, 1602, 1580, 1518, 1486, 1452,1372, 1316, 1246, 1178, 1154, 1108, 1070, 1000, 982, 946, 856, 802, 776,710, 628, 538 cm⁻¹.

¹ H-NMR (acetone-d₆ /D₂ O) δ: 8.05 (2H, d), 7.92 (2H, d), 7.65 (1H, dd),7.58-7.35 (9H, m, overlap), 7.23 (1H, dd), 6.38 (1H, s), 6.08 (1H, t),5.65 (1H, d), 5.60 (1H, d), 5.10 (1H, br.s), 4.99 (1H, d), 4.97 (1H,br.s), 4.80 (1H, d), 4.28 (1H, dd), 4.11 (2H, s), 3.79 (1H, d), 2.94(1H, m), 2.35 (3H, s), 2.35-2.10 (1H, m), 2.13 (3H, s), 1.95 (3H, s),1.84 (1H, m), 1.67 (3H, s), 1.13 (6H, s, overlap).

Example 2 Alternate Method for the Preparation of7-O-phosphonooxymethylpaclitaxel (a) Preparation of2'-O-(benzyloxycarbonyl)paclitaxel ##STR48##

To a stirred solution of paclitaxel (150 mg, 0.176 mmol) andN,N-diisopropylethylamine (93 μL, 0.534 mmol, 3 eq.) in anhydrousmethylene chloride (4 mL) at room temperature was added benzylchloroformate (75 μL, 0.525 mmol, 3 eq.). The reaction mixture wasstirred at room temperature for 3 h, concentrated to 2 mL, and purifiedon a silica gel column, using 1:1 of ethyl acetate/hexanes as eluant, toobtain the title compound as a white powder (150 mg, Y: 86%). MP140°-150° C. (decomposition).

(b) Preparation of2'-O-(benzyloxycarbonyl)-7-O-methylthiomethylpactitaxel ##STR49##

To a cooled (dry ice--CCl₄ ; -30° C. bath temp.) solution of2'-O-(benzyloxycarbonyl)paclitaxel (4.935 g; 5.0 mmol) in dryacetonitrile (80 ml) was added in succession dimethylsulfide (3.6 ml; 40mmol) and benzyol peroxide (4.9 g; 20.247 mmol). After 10 mins. at -30°C., the cold bath was removed and the reaction mixture was stirredvigorously for 2 hr at room temperature. The reaction mixture was thendiluted with ethyl acetate to a volume of 200 ml and washed with waterand brine. The organic layer was dried (MgSO₄), and the solvent was thenevaporated to give a residue which was kept under vacuum for 18 h toremove any dimethylsulfoxide that was present as a reaction sideproduct. The residue was purified on a silica gel column using firstethyl acetate: hexane (1:2) as eluant to remove the less polarimpurities, followed by ethyl acetate: hexane (1:1) to give the expectedtitle compound as a foam. This was triturated with dry ether andfiltered to give the title compound as a fluffy solid (5.0 g, 95%). MP120°-122° C.

MS (FAB): [MH]⁺, m/z 1048; [M+Na]⁺, m/z 1070; [M+K]⁺, m/z 108

IR (KBr): 3440, 3066, 1750, 1722, 1664, 1602, 1583, 1538 cm⁻¹.

NMR (CDCl₃) δ: 1.177 (3H, s) 1.236 (3H, s) 1.745 (3H, s) 2.023 (3H, s)2.121 (3H s) 2.162 (3H, s) 2.436 (3H, s) 3.887 (H, d) 4.134 (H, d) 4.197(H, d) 4.295 (H, m) 4.964 (H, d) 5.161 (2H, d) 5.450 (H, d) 5.703 (H, d)5.981 (H, dd) 6.257 (H, t) 6.541 (H, s) 6.920 (H, d, NH) 7.322-8.22(15H, m).

The title compound was also prepared by the following alternativemethod:

To a solution of 2'-O-(benzyloxycarbonyl)paclitaxel (2.0 g; 2.0263 mmol)in dry dimethylsulfoxide (10 ml) was added dropwise acetic anhydride (10ml). The resulting mixture was stirred at room temperature for 18 hunder N₂, diluted with ethyl acetate (100 ml), and washed carefully withcold 6% sodium bicarbonate solution (6×30 ml), cold water (6×30 ml) andbrine. The organic layer was dried (MgSO₄), and the solvent wasevaporated to give a residue. This was purified by silica gel column andeluted with methylene chloride, methylene chloride-5% acetonitrile, andmethylene chloride-10% acetonitrile to give the expected title compound(1.86 g, 87.7%). This compound is identical to that obtained via thepreviously described dimethyl sulfide/benzoyl peroxide method.

(c) Preparation of2'-O-(benzyloxycarbonyl)-7-O-dibenzylphosphonooxymethylpaclitaxel##STR50##

To a solution of 2'-O-(benzyloxycarbonyl)-7-O-methylthiomethylpaclitaxel(5.0 g; 5.5396 mmol) in dry 1,2-dichloroethane (120 ml) was addedactivated powdered 4 Å molecular sieves (5.0 g). To this mixture wasadded dropwise at room temperature a solution mixture ofN-iodosuccinimide (1.61 g; 7.1632 mmol) and dibenzyl phosphate (1.97 g;7.1632 mmol) in dry tetrahydrofuran (90 ml). After stirring vigorouslyat room temperature for 30 min. the reaction mixture was filtered overCelite and the filtrate was evaporated to dryness to give a red residue.The residue was taken up in ethyl acetate (100 ml), washed with cold 6%NaHSO₃ solution (2×50 ml), cold 6% NaHCO₃ solution (2×50 ml) and brine(1×50 ml). The organic layer was dried (MgSO₄) and the solvent wasevaporated to give a solid mass which was triturated with dry ether andfiltered to give the title compound as an ivory colored solid (5.9 g,97%). MP 124°-127° C.

MS (FAB): [MH]⁺, m/z 1278; [M+Na]⁺, m/z 1301; [M+K]⁺, m/z 1316

IR (KBr): 3430, 3066, 3032, 1750, 1726, 1664, 1582, 1532 cm⁻¹

NMR (CDCl₃) δ: 1.160 (3H, s) 1.703 (3H, s) 1.985 (3H, s) 2.164 (3H, s)2.420 (3H, s) 3.854 (H, d) 4.151 (H, d) 4.216 (H, m) 4.298 (H, d) 4.873(H, d) 5.043 (6H, m) 5.140 (2H, d) 5.417 (H, d) 5.670 (H, d) 5.971 (H,dd) 6.241 (H, t) 6.317 (H, s) 6.912 (H, d, NH) 7.280-8.115 (25H, m).

(d) Preparation of 7-O-phosphonooxymethylpaclitaxel

To a solution of2'-O-(benzyloxycarbonyl)-7-O-dibenzylphosphonooxymethylpaclitaxel (6.0g; 4.7095 mmol) in ethyl acetate (120 ml) was added 10% Pd/C (6.0 g) andthe mixture was hydrogenated at 60 psi (400 kPa) for 24 hr. The reactionmixture was filtered over Celite and the solvent was evaporated to give4.07 g of a crude residue. This was purified on a short silica gelcolumn by successive elution with chloroform: 10%, 20% and 40% methanolto give the title compound as a white solid (3.2 g, 71%) MP 155°-158° C.

This product has the same Rf(TLC) and same retention time (HPLC) as anauthentic sample.

MS (FAB): [MH]⁺, m/z 964; [M+Na]⁺, m/z 986; [M+K]⁺, m/z 1002; [M+K⁺ +Na⁺-H]⁺, m/z 1024; [M+2K-H]⁺, m/z 1040

UV (MeOH): λmax=230 nm, E(1%/1 cm)=252.5

IR (KBr): 3432, 3066, 2992, 1722, 1648, 1602, 1580, 1522, 1488, 1452,1372, 1316, 1246, 1178, 1154,, 1110, 1070, 1000, 980, 946, 854, 802,776, 710, 628, 538 cm⁻¹.

¹ NMR (acetone-d₆ /D₂ O), δ: 1.08 (3H, s), 1.10 (3H, s), 1.63 (3H, s),1.88 (3H, s), 1.96 (H, m), 2.13 (3H, s), 2.32 (3H, s), 2.89 (H, m), 3.76(H, d), 4.19 (H, m), 4.89 (H, dd), 5.09 (H, dd), 5.55-5.60 (2H,overlapping d's), 6.04 (H, t), 6.32 (H, s), 720 (H, t), 7.34-7.67 (10H,overlapping m's), 7.87 (2H, dd), 8.02 (2H, dd).

Example 3 2'-O-(ethoxycarbonyl)-7-O-phosphonooxymethylpaclitaxel (a)Preparation of 2'-O-(ethoxycarbonyl)paclitaxel ##STR51##

To a solution of paclitaxel (4.35 g, 5.1 mmol) in dry methylene chloride(51 ml) was added N,N-diisopropylethylamine (2.67 ml, 15.3 mmol),followed by ethyl chloroformate (1.46 ml, 15.3 mmol). The reactionmixture was stirred at 0° C. for 2 hrs, and then at room temperature foran additional 1 hr. The reaction mixture was diluted with ethyl acetate(400 ml), the organic phase was washed with saturated solution of NaHCO₃(2×30 ml), and with brine (30 ml). The resulting organic phase was driedover MgSO₄ to provide crude title compound (93%) which was used in thenext step without further purification.

MS (FAB/NOBA, NaI, KI): [M+H]⁺, m/z 926; [M+Na]⁺, m/z 948; [M+K]⁺, m/z964

HRMS (FAB/NOBA, CsI/Gly external reference): [M+H]⁺ m/z 926.3588observed, C₅₀ H₅₆ NO₁₆, calculated value: 926.3599 (deviation Δ=1.2 ppm)

¹ HNMR (CDCl₃): δ 1.13 (3H, s), 1.23 (3H, s), 1.30 (3H, t), 1.67 (3H,s), 1.92 (3H, s), 2.21 (3H, s), 2.37 (H, d), 2.45 (3H, s), 2.54 (H, m),3.80 (H, d), 4.15-4.32 (4H, m's overlapping), 4.43 (H, dd), 4.96 (H, d),5.42 (H, d), 5.68 (H, d), 5.98 (H, dd), 6.28 (2H, m's, overlapping),7.00 (H, d), 7.34-7.59 (11H, m's overlapping), 7.74 (2H, d), 8.12 (2H,d).

Alternate Run:

Paclitaxel (5.40 g, 6.324 mmol) in dry dichloromethane (63 mL) wascooled to 0° C. and treated with neat N,N-diisopropylethylamine (3.30mL, 3 equiv) and then neat ethyl chloroformate (1.81 mL, 3 equiv)dropwise over a 5 min period. The reaction was monitored by TLC (50%ethyl acetate in hexane). After 2 h at 0° C. and 16 h at roomtemperature, the reaction was complete and the yellow-orange solutionwas diluted with ethyl acetate (300 mL) and washed with saturated sodiumbicarbonate (3×75 mL) and brine (75 mL). Drying (MgSO₄) and evaporationafforded crude title compound, which was purified by precipitation:dichloromethane (ca. 100 mL) was added followed by cooling and additionof hexane (ca 60 mL) to the cloud point. After cooling in ice forseveral hours, the solid was collected by filtration. Yield 5.17 g(88%).

Alternate Run:

In a flame dried, single necked 3 L flask was dissolved paclitaxel (99.0g, 115.9 mmol) in 1,350 mL of dry methylene chloride under the argonatmosphere. The solution was cooled to -10°. N,N-diisopropylethylamine(52.4 g, 405.7 mmol) was added slowly (addn. time ˜13 min.), followed byClCO₂ Et (31.45 g, 289.8 mmol; addn. time ˜15 min.). The resultingmixture was stirred overnight (16 hrs.) at -4° C. The reaction wasjudged incomplete by TLC. Another charge of N,N-diisopropylethylamine(2.62 g, 20.28 mmol) was added, followed by ClCO₂ Et (2.20 g, 20.28mmol) and the stirring was continued for 3 hrs at -4° C. No startingmaterial was detected by TLC. The cold mixture was diluted with ethylacetate (1.5 L) and transferred to a separatory funnel. It was thenwashed with 5% KHSO₄ (2×500 mL), water (1×500 mL), 5% KHSO₄ (1×500 mL),water (1×500 mL), satd. NaHCO₃ (2×500 mL) and brine (2×500 mL), dried(MgSO₄) and the solvents were removed in vacuo to give 147 g of thecrude product. The residue was dissolved in hot methylene chloride (800mL, bath temp. 42° C.) and hexanes were added dropwise (530 mL) withstirring, while the temperature was maintained. The crystallizingmixture was set aside for 3 hrs. at room temperature and then in thecold room (0° C.) overnight. The heavy white crystals were collected byfiltration and washed with hexanes/CH₂ Cl₂ 1:1 (v/v) (2×200 mL). Afterdrying on the suction filter for 1 hr. it was dried in vacuo (˜1.0 mmHg)overnight to give 95.7 g (89% yield) of the title compound (homogeneityindex as measured by HPLC=98.5%).

(b) Preparation of 2'-O-(ethoxycarbonyl)-7-O-methylthiomethylpacitaxel##STR52##

To a solution of 2'-O-(ethoxycarbonyl)paclitaxel (4.38 g, 4.7 mmol) indry dimethylsulfoxide (12.5 ml) was added acetic anhydride (12.5 ml).The reaction mixture was stirred for 24 hrs at room temperature and thendiluted with ethyl acetate (500 ml), washed with saturated solution ofNaHCO₃ (3×40 ml) and with water (2×40 ml). The resulting organic layerwas dried over MgSO₄, and the solvents were evaporated in vacuo todryness. The residue was purified by silica gel chromatography (40%ethyl acetate in hexanes) to afford the desired title compound (4.39 g,94%).

MS (FAB/NOBA, NaI, KI): [M+H]⁺, m/z 986; [M+Na]⁺, m/z 1008; [M+K]⁺, m/z1024

HRMS (FAB/NOBA, CsI/Gly external reference): [M+H]⁺ m/z 986.3646(calculated value: 986.3633, deviation Δ=1.3 ppm)

¹ HNMR (CDCl3) δ: 1.18 (3H, s), 1.20 (3H, s), 1.30 (3H, s), 1.75 (3H,s), 1.84 (H, m), 2.09 (3H, s), 2.11 (3H, s), 2.16 (3H, s), 2.24 (H, d),2.37 (H, d), 2.45 (3H, s), 2.80 (H, m), 3.68 (H, d), 4.08-4.33 (5H, m,overlapping), 4.65 (2H, s), 4.96 (H, d), 5.43 (H, d), 5.69 (H, d), 5.98(H, dd), 6.26 (H, t), 6.55 (H, s), 7.00 (H, d), 7.32-7.61 (11H, m,overlapping), 7.73 (2H, dd), 8.11 (2H, dd).

Alternate Run:

2'-O-(Ethoxycarbonyl)paclitaxel (2.260 g, 2.4406 mmol) was dissolved inanhydrous dimethylsulfoxide (6 mL), and acetic anhydride (6 mL) wasadded in one lot at room temperature. The reaction was monitored by HPLC(C18 analytical column; 60% acetonitrile-40% 10 mM ammoniumphosphatebuffer, pH 6). After 30 h, the solution was diluted with ethyl acetate(250 mL) and washed with saturated aqueous bicarbonate (3 times) thenwater and brine. After drying over magnesium sulfate and filtration, thecrude product was chromatographed on silica (40% ethyl acetate inhexane) to yield the title compound as a white foam (2.030 g, 91%) thatwas 90% pure by HPLC. A portion was further purified by a second column(5% acetonitrile in dichloromethane) to afford material that was ca. 97%pure by HPLC.

Alternate Method for the Preparation of2'-O-(ethoxycarbonyl)-7-O-methylthiomethylpaclitaxel

2'-O-(Ethoxycarbonyl)paclitaxel (4.170 g, 4.503 mmol) was dissolved inanhydrous acetonitrile (68 mL) at -40° C., and dimethyl sulfide (3.2 mL,44.10 mmol) was added, followed by benzoyl peroxide (4.400 g, 18.24mmol). The mixture was placed in an ice bath and stirred at 0° C., andthe course of the reaction was monitored by TLC (40% ethyl acetate inhexane). After 3 h. no starting material was detected, and the solutionwas worked up by adding ethyl acetate (250 mL) and saturated aqueoussodium bicarbonate (100 mL). The organic phase was further washed withbicarbonate, water, and brine, then dried over magnesium sulfate andfiltered. The residue was purified by silica gel flash chromatography(4% acetonitrile in dichloromethane), to yield the title compound as awhite foam (2.571 g, 58% yield). The purity of this sample was judgedas >97% by HPLC. The NMR spectrum was identical to the one reportedabove.

Alternate Run for Preparing2'-O-(ethoxycarbonyl)-7-O-methylthiomethylpaclitaxel

2'-O-(Ethoxycarbonyl)paclitaxel (49.3 g, 53.2 mmol) was placed in aflame dried single necked 1 L flask and dissolved in dry acetonitrile(500 mL) at room temperature. Methyl sulfide (39.1 mL, 0.532 mol) wasrapidly added via syringe. The stirred reaction mixture was cooled to-16° C. in an ice/salt bath and solid benzoyl peroxide (51.6 g, 0.213mol) was added to the mixture in one lot. (Full four equivalents arerequired for the reaction to proceed to completion.) Stirring wascontinued for 30 minutes, during which time the temperature rose to˜-10° C. The reaction medium remained heterogeneous throughout thisperiod (benzoyl peroxide has not dissolved completely). The cooling bathwas changed to ice/water, the temperature was raised to 0° C. and theremaining benzoyl peroxide dissolved ˜5 min. after the warm-up. Thereaction was judged complete by TLC after stirring at 0° C. for another2.5 hours. The volume of the solution was reduced ˜200 mL by removingthe solvent on a rotovap and it was then transferred to a separatoryfunnel where it was washed with heptane (5×500 mL). The acetonitrilelayer was diluted with ethyl acetate (1.5 L) and washed with a 3:1mixture satd. NaHCO₃ /5% K₂ CO₃ (v/v) (2×500 mL), satd. NaHCO₃ (2×500mL), half-satd. brine (1×500 mL) and brine (1×500 mL), dried (MgSO₄) andthe solvents were removed in vacuo to give 67.0 g of the crude product.It was dissolved in acetone (200 mL), warmed to 40° C. in a water bathand hexanes were added dropwise with stirring until the cloudiness wasobserved (400 mL). The crystallizing mixture was set aside for 3 hrs. atroom temperature and then transferred to a cold room (0° C.) where itwas kept overnight (16 hrs.). A thick cake was formed. The solid wascollected by filtration and washed with hexanes/acetone 3:1 (v/v) (2×50mL). The resulting white crystals were dried on the suction filter for 1hr. and then in vacuo (˜0.5 mmHg) overnight to give 47.5 g (91% yield)of the title compound (homogeneity index as measured by HPLC=94.8%).

(c) Preparation of2'-O-(ethoxycarbonyl)-7-O-dibenzylphosphonooxymethylpaclitaxel ##STR53##

A solution of N-iodosuccinimide (1.953 g, 8.65 mmol) and dibenzylphosphate (2.41 g, 8.65 mmol) in tetrahydrofuran was added to a mixtureof 2'-O-(ethoxycarbonyl)-7-O-methylthiomethylpaclitaxel (5.677 g, 5.76mmol) and 4 Å molecular sieves (5.7 g) in methylene chloride (100 ml) atroom temperature. The reaction mixture was stirred for 40 min. at roomtemperature. After this period the reaction was complete as judged byTLC. The reaction mixture was filtered through Celite and the filtratewas concenterated in vacuo to give a brownish residue which was dilutedwith ethyl acetate (800 ml), the organic phase was washed with 1% Na₂SO₃ (2×80 ml), then washed with 5% brine (2×50 ml). The organic phasewas concentrated in vacuo and dried. Chromatography of the resultingresidue (50-60% ethyl acetate in hexanes) gave the desired titlecompound (6.23 g, 89%).

MS (FAB/NOBA, NaI, KI): [M+Na]⁺, m/z 1238; [M+K]⁺, m/z 1254

HRMS (FAB/NOBA, CsI/Gly external reference): [M+Na]⁺ m/z 1216.4291 (C₆₅H₇₁ NO₂₀ P calculated value: 1216.4307; deviation Δ=1.3 ppm)

¹ HNMR (CDCl₃), δ: 1.18 (3H, s), 1.21 (3H, s), 1.30 (3H, t), 1.67 (6H,s), 1.80 (H, s), 1.93 (H, m), 1.99 (3H, d), 2.18 (3H, s), 2.23 (H, m),2.38 (H, m), 2.45 (3H, s), 2.80 (H, m), 3.86 (H, d), 4.14-4.32 (5H, m's,overlapping), 4.88 (H, d), 5.00-5.07 (4H, m's, overlapping), 5.42 (H,d), 5.68 (H, d), 5.96 (H, dd), 6.26 (H, t), 6.33 (H, s), 6.95 (H, d),7.30-7.61 (11H, m's overlapping), 7.75 (2H, dd), 8.12 (2H, dd).

Alternate Run:

To a solution of 2'-O-(ethoxycarbonyl)-7-O-methylthiomethylpaclitaxel(350 mg, 0.355 mmol) in anhydrous tetrahydrofuran (8 mL) was added asolution of N-iodosuccinimide (120 mg, 0.532 mmol) and dibenzylphosphate (148 mg, 0.532 mmol) in tetrahydrofuran (5 mL). The reactionwas monitored by HPLC (C18 column; 70% acetonitrile, 30% 10 mM ammoniumphosphate, pH 6). After 2h, less than 5% starting material was detected,and the reaction was worked-up. The solution was diluted with ethylacetate (75 mL), and washed with 1% aqueous sodium bisulfite (2×50 mL)and brine (50 mL). After quick drying over magnesium sulfate andfiltration, the solvent was evaporated. Silica gel flash chromatography(45% ethyl acetate/hexane) provided the title compound as a white foam(281 mg, 65%). HPLC analysis indicated a purity of ca. 95%.

Alternte Run:

Crushed 4 A molecular sieves were placed in a flame dried one-necked 1 Lflask which was then connected to a vacuum line (˜0.5 mmHg). The sieveswere heated with a heatgun for ˜10 min. while being shaken manually.After cooling under vacuum argon was introduced into the flask and2'-O-(ethoxycarbonyl)-7-O-methylthiomethylpaclitaxel (37.5 g, 38.03mmol) was added, followed by dibenzyl phosphate (14.8 g, 53.24 mmol) andTHF (400 mL). The heterogeneous mixture was vigorously stirred for 15min. at room temperature with a magnetic stirrer. In a separate flamedried flask, N-iodosuccinimide (10.7 g, 47.54 mmol) was dissolved in THF(50 mL) under argon. (During the preparation of the NIS solution, liquidtransfer and during the reaction course, the vessels were covered withaluminum foil for protection against light.) It was then added slowly(10 min) to the reaction mixture via a syringe. The flask containing NISwas washed with 5 mL of THF and transferred to the reaction mixture,which was then stirred for 2 hrs. at room temperature. TLC analysisshowed absence of the starting material. The deeply red colored solutionwas filtered through a pad of Celite® directly into a vigorously stirredbi-phasic mixture containing ethyl acetate (500 mL), 10% aq. sodiumthiosulfate (300 mL) and satd. sodium bicarbonate (200 mL). The redcolor disappeared in a few seconds giving a colorless solution. TheCelite® pad was washed with EtOAc (˜100 mL) and both liquid layers weretransferred into a separatory funnel. The organic layer was diluted with1 L of EtOAc, the layers were separated and the organic layer was washedwith a mixture of satd. NaHCO₃ and 5% K₂ CO₃ (3:1 v/v, 2×500 mL), thensatd. NaHCO₃ (2×500 mL), half-saturated brine (1×500 mL) and brine(1×500 mL). The extract was dried with anhydrous MgSO₄ and filtered. Itwas treated with 5.0 g of neutral Norit (charcoal) by stirring at roomtemperature for 15 min. It was filtered again through a Celite® pad andthe solvent was removed under the reduced pressure to give 52 g of thecrude product. It was dissolved in toluene/methylene chloride (280 mL/25mL) and hexanes were added dropwise (20 mL). After being set aside for 3hrs. at room temperature the crystallizing mixture was left at 0° C.overnight. A pale yellow solid was formed on the flask walls. Afterdecanting the mother liquor, the residue was triturated with toluene (50mL), filtered, washed with toluene and dried on the suction filter for30 min. It was then transferred to a desiccator with Drierite® andfurther dried in vacuo (˜0.5 mmHg) for four hours to give 24.4 g (53%yield) of the title compound (homogeneity index as measured byHPLC=95.9%). The mother liquor was evaporated to dryness, trituratedwith toluene (100 mL), filtered, washed with toluene and dried on thesuction filter for 30 min. After drying in a desiccator as describedabove it gave 12.5 g (27% yield) of the same product (homogeneity indexas measured by HPLC=97.1%).

(d) Preparation of2'-O-(ethoxycarbonyl)-7-O-phosphonooxymethylpaclitaxel; Its Monosodium,Monopotassium, Triethylamine, Arginine, Lysine, Ethanolamine,N-methylglucamine, and Triethanolamine Salts ##STR54##

To a solution of2'-O-(ethoxycarbonyl)-7-O-dibenzylphosphonooxymethylpaclitaxel (1.23 g,1.01 mmol) in dry ethyl acetate (40 ml) was added 10% Pd on carbon (428mg, 10%, 0.404 mmol). The reaction mixture was subjected tohydrogenation (60 PSI=400 kPa) with continuous shaking for 24 hrs. Thesolid was filtered off through Celite, then the Celite was rinsedseveral times with ethyl acetate. The filtrate was concentrated to givefree acid form of the title compound (1.01 g, 80% purity as judged byHPLC). The impurities were removed at the next step by preparative C-18column chromatography.

MS (FAB/NOBA, NaI, KI): [M+Na]⁺, m/z 1058; [M+K]⁺, m/z 1074; [M+2Na-H]⁺,m/z 1080; [M+Na+K-H]⁺, m/z 1096; [M+2K-H]⁺, m/z 1112

HR-MS (FAB/NOBA, CsI/Gly, external reference): [M+Na]⁺, m/z 1058.3163(C₅₁ H₅₈ NO₂₀ PNa calculated value: 1058.3188; deviation Δ=2.3 ppm)

¹ H NMR (acetone-d₆ /D₂ O) δ: 1.13 (3H, s), 1.21 (3H, s), 1.66 (3H, s),1.87 (H, m), 1.93 (3H, s), 2.14 (3H, s), 2.18 (H, m), 2.44 (3H, s), 2.95(H, m), 3.81 (H, d), 4.12 (2H, s), 4.15-4.27 (3H, m's overlapping),4.92-4.99 (2H, br.m's overlapping), 5.15 (H, br.s), 5.48 (H, d), 5.61(H, d), 5.84 (H, dd), 6.07 (H, t), 6.36 (H, s), 7.25 (H, t), 7.28-7.69(10H, m's overlapping), 7.89 (2H, dd), 8.08 (2H, dd), 8.86 (H, d).

Alternate Run:

2'-O-(Ethoxycarbonyl)-7-O-(dibenzylphosphonooxymethyl)paclitaxel (490mg, 0.402 mmol) in ethyl acetate (20 mL) was hydrogenated in a Parrshaker at 60 psi (400 kPa) in the presence of palladium on characoal(10% w/w, 150 mg). Monitoring was carried out by TLC and HPLC. When nomore starting material nor an intermediate (presumably the monobenzylphosphate) were detected (26 h), the suspension was filtered throughCelite and evaporated to dryness. HPLC analysis showed a purity of88-92%.

Alternate Run:

2'-O-(Ethoxycarbonyl)-7-O-phosphonooxymethylpaclitaxel triethylaminesalt to be described below (5.4 g, 4.75 mmole) was partitionedvigorously between EtOAc (100 mL) and 5% NaHSO₄ (45 ml) with stirring at0° C. for 30 minutes. The aqueous layer was separated and extracted withEtOAc (20 ml). The combined EtOAc layer was washed with half-brine (25ml), brine (25 mL×2), dried over NaSO₄ and filtered to give a solutionof the acid (˜4.75 mmole) in EtOAc (˜150 mL). This EtOAc solution wasthen concentrated to dryness on a rotary evaporator to give 3.75 g ofthe title compound in free acid form in 95% yield. HPLC analysis showedhomogeneity index of 96.1%.

The monosodium salt was prepared as follows:

A sample of 2'-O-(ethoxycarbonyl)-7-O-phosphonooxymethylpaclitaxel (1.6g, 1.55 mmol) was dissolved in acetonitrile (30 ml) by sonication. Thissolution was diluted with water (30 ml) and 1.1M solution of NaHCO₃(2.11 ml, 2.32 mmol) was added, alternately shaking and sonicating toobtain a solution (5-20 min). The somewhat milky solution was appliedonto a C-18 column, washing with two column volumes of water, theneluting the monosodium salt with 25% acetonitrile/water. The appropriatefractions were pooled, the acetonitrile evaporated, and the aqueousphase lyophilized, to yield the monosodium salt of the title compound(850 mg, ca 50%), having HPLC purity of 97%.

MS (FAB/NOBA, NaI, KI): [M+Na]⁺, m/z 1180

HR - MS (FAB/NOBA, CsI/Gly external reference): [M+Na]⁺, m/z 1080.2968(C₅₁ H₅₇ NO₂₀ PNa₂ calculated value: 1080.3007; deviation D=3.6 ppm)

Elemental analysis: C: 52.65 (calc. 56.72), H: 5.06 (calc. 5.23), N:1.20 (calc. 1.30), Na: 2.74 (calc. 2.12)

IR (KBr): 3430, 3066, 2988, 1746, 1722, 1660, 1602, 1582, 1526, 1488,1452, 1374, 1246, 1178, 1150, 1108, 1070, 1052, 1026, 1002, 966, 912,834, 792, 776, 710, 628, 538 cm⁻¹.

¹ H-NMR (DMSO-d₆, D₂ O, acetone-d₆) δ: 1.10 (6H, s), 1.23 (3H, t), 1.64(3H, s), 1.70 (H, m), 1.90 (3H, s), 1.99 (H, m), 2.14 (3H, s), 2.37 (3H,s), 2.98 (H, m), 3.74 (H, d), 4.07 (2H, s), 4.13-4.26 (3H, m,overlapping), 4.80 (H, br.dd), 4.97 (H, d), 5.09 (H, br.t), 5.44 (H, d),5.55 (H, d), 5.99 (H, t), 6.34 (H, s), 7.22 (H,t), 7.43-7.69 (10H, m,overlapping), 7.92 (2H, dd), 8.06 (2H, dd).

The sodium salt can also be prepared as follows:

Crude 2'-O-(ethoxycarbonyl)-7-O-phosphonooxymethylpaclitaxel (89%; 70mg, 0.060 mmol), in EtOAc (2 ml) was treated with a solution of sodiumethylhexanoate (87.5 mM in EtOAc, 1.0 ml, 0.0875 mmol) at roomtemperature with stirring. After stirring at room temperature for 1 h,hexane (1.2 ml) was added to the cloud point. After storing at -20° C.for 2 h, the fine amorphous powder was filtered (with some difficulty,very slow) through fine filter paper, to yield 45 mg (70%) of the sodiumsalt. This was 95.2% pure by HPLC and contained a small amount ofethylhexanoic acid (NMR).

The triethanolamine salt was prepared as follows:

2'-O-(Ethoxycarbonyl)-7-O-phosphonooxymethylpaclitaxel, crude from thehydrogenation (89% by HPLC) (0.69 g, 0.593 mmol after correction forimpurities) was dissolved in ethyl acetate (10 ml), and stirred slowlywhile a solution of triethanolamine (0.11M in EtOAc, used 5.1 ml, 0.95eq) was added dropwise. The milky solution obtained by this procedurewas digested at 0° C. for 2 h, then filtered on file filter paper,rinsing with cold EtOAc. Yield: 499 mg (80%) of an amorphous, fine,non-electrostatic powder that was dried overnight in vacuo. HPLC shows96.6% purity (C-18, 45% 5 mM Q₁₂ +10 mM ammonium phosphate pH 6, 55%actonitrile). NMR spectrum (D₂ O/acetone/DMSO) shows traces of ethylacetate and no other clearcut impurities. It analyzes for a 2-3×hydrate.

The triethanolamine salt of lesser priority obtained from anotherexperiment was further purified by the following procedure. Thetriethanolamine salt (approx. 2 g) was dissolved in about 30%acetonitrile/water. This solution was eluted with slight nitrogenpressure through a column of C18 (Bakerbond) with a gradient of 20% to40% acetonitrile in water. The fractions containing the desiredtriethanolamine salt were collected; the acetonitrile was removed byrotary evaporation under reduced pressure. The aqueous solutions werefrozen and lyophilized overnight to afford 1.4 grams of thetriethanolamine salt with a purity of 97.5%.

The triethanolamine salt can also be prepared as follows:

2'-O-(Ethoxycarbonyl)-7-O-phosphonooxymethylpaclitaxel triethylaminesalt (3.0 g, 2.64 mmole) was partitioned between EtOAc (60 ml) and 5%NaHSO₄ (30 ml) with vigorous stirring at 0° C. for 15 minutes. Theaqueous layer was separated and extracted with EtOAc (10 mL). Thecombined EtOAc layer was washed with brine (15 ml), dried over Na₂ SO₄,filtered to give a solution of the acid (˜2.64 mmole) in EtOAc (˜70 ml).To this EtOAc solution at room temperature was added dropwise withvigorous stirring N(CH₂ CH₂ OH)₃ (0.35 ml, 2.64 mmole) over a period of5 minutes. The resulting suspension was stirred for an additional 1 hrand then it was filtered, washed with EtOAc (15 ml×2), dried in vacuo togive 2.8 g of the triethanolamine salt in 89% yield. HPLC analysisshowed homogeneity index of 98.7%; mp.: >157° C. with decomposition.

Elemental analysis calculated for C₅₆ H₇₃ N₂ O₂₃ P.2.0 H₂ O.0.3 EtOAc:C, 55.60; H, 6.48; N, 2.27; KF (H₂ O), 2.92. Found: 55.94; H, 6.59; N,2.43; KF (H₂ O), 3.50.

The triethylamine salt was prepared as follows:

To the solution of2'-O-(ethoxycarbonyl)-7-O-dibenzylphosphonooxymethylpaclitaxel (10 g,8.23 mmole), in EtOAc (350 ml), at room temperature was added 10% Pd oncarbon (2 g, 20% load). The resulting suspension was degassed byevacuating air and then purging with argon. This process was repeatedtwo additional times. The argon then was replaced with hydrogenfollowing the same degassing procedure. The resulting suspension wasstirred under a balloon hydrogen pressure (2-3 pound per square inch)for 16 hr at room temperature with vigorous stirring. The hydrogen wasevacuated and replaced with argon three times following the degassingprocedure. The resulting suspension was filtered through a pad ofCelite. To this homogeneous filtrate was slowly added Et₃ N (8.23 mmole,1.14 mL) over a period of 5 min with vigorous stirring. The resultingfine white suspension was stirred for an additional 30 min. It wasfiltered through a fritted funnel. The filter cake was dried in vacuo (1mmHg) for 16 hr to give 8.22 g of the title triethylamine salt in 88%yield. HPLC analysis showed homogeneity index of 97.4%; mp.: >178° C.with decomposition.

Elemental analysis calculated for C₅₇ H₇₃ N₂ O₂₀ P.4.5 H₂ O: C, 56.19;H, 6.79; N, 2.30; KF (H₂ O), 6.65. Found: 56.33; H, 6.87; N, 2.32; KF(H₂ O), 7.96.

Alternate run for making the triethylamine salt:

2'-O-(Ethoxycarbonyl)-7-O-dibenzylphosphonooxymethylpaclitaxel (5.67 g,4.66 mmol) was added to a 250 mL flask and dissolved in ethyl acetate(150 mL). The flask was equipped with a three-way valve with oneconnection to house vacuum and one connection to an argon line. Usingthe valve, the flask was partially evacuated and then purged with argon.This process was repeated two additional times. Palladium on activatedcarbon (10% Pd) (0.85 g) was added to the flask. The argon line attachedto the three-way valve was replaced with a hydrogen-filled balloon.Using the valve, the flask was partially evacuated and then purged withhydrogen. This process was repeated four additional times. The resultingmixture was stirred at room temperature under the hydrogen balloonatmosphere overnight. TLC analysis 17 hours after the initial exposureto hydrogen showed the starting material to be absent. The hydrogenballoon attached to the three-way valve was replaced with an argon line.Using the valve, the flask was partially evacuated and then purged withargon. This process was repeated two additional times. The contents ofthe flask were vacuum-filtered through a pad of Celite. The Celite wasrinsed with ethyl acetate (2×10 mL). To the stirring filtrate was addedNEt₃ (0.650 mL, 4.66 mmol). The resulting suspension was stirred at roomtemperature for two hours, and the volume was then reduced to ˜150 mLvia a rotovap. The solid was filtered, washed with ethyl acetate (2×10mL) and dried under vacuum to give 4.76 g (90% yield) of the titletriethylamine salt as a white powder (homogeneity index of the productwas determined to be 96.6% by HPLC analysis).

Alternate run for making the triethylamine salt:

2'-O-(Ethoxycarbonyl)-7-O-dibenzylphosphonooxymethylpaclitaxel (5.17 g,4.25 mmol) was added to a 250 mL flask and dissolved in ethyl acetate(150 mL). The flask was equipped with a three-way valve with oneconnection to house vacuum and one connection to an argon line. Usingthe valve, the flask was partially evacuated and then purged with argon.This process was repeated two additional times. Palladium on activatedcarbon (10% Pd) (0.86 g) was added to the flask. The argon line attachedto the three-way valve was replaced with a hydrogen-filled balloon.Using the valve, the flask was partially evacuated and then purged withhydrogen. This process was repeated five additional times. The resultingmixture was stirred at room temperature under the hydrogen balloonatmosphere overnight. TLC analysis 16 hours after the initial exposureto hydrogen showed the starting material to be absent. The hydrogenballoon attached to the three-way valve was replaced with an argon line.Using the valve, the flask was partially evacuated and then purged withargon. This process was repeated two additional times. The contents ofthe flask were vacuum-filtered through a pad of Celite. The Celite wasrinsed with ethyl acetate (4×10 mL). To the stirring filtrate was addedNEt₃ (0.590 mL, 4.25 mmol). The resulting suspension was stirred at roomtemperature for one hour, and the volume was then reduced to ˜140 mL viaa rotovap. The solid was filtered, washed with ethyl acetate (10 mL) anddried under vacuum to give 4.46 g (92% yield) of the title triethylaminesalt as a white powder (homogeneity index as determined by HPLC analysiswas 96.7%).

The lysine salt was prepared as follows:

2'-O-(ethoxycarbonyl)-7-O-dibenzylphosphonooxymethylpaclitaxel (15.0 g,12.34 mmole) was added portionwise to a suspension of 10% palladium oncarbon (20% load, 3 g) in EtOH (600 ml, 200 proof) at 0° C. Theresulting suspension was degassed by evacuating air and purging withargon. This process was repeated two additional times. The argon thenwas replaced with hydrogen following the same degassing procedure withvigorous stirring. The resulting mixture was stirred at 0° C. for 2 hrs.The cooling bath was removed and the reaction solution was stirred atambient temperature for additional 41/2 hrs. The reaction mixture wasdegassed by evacuating hydrogen and purging with argon three times. Itwas filtered under argon through a pad of Celite. To the resultingfiltrate was slowly added a solution of lysine (1.63 g, 0.94 eq) in a1:1 mixture of H₂ O:EtOH (200 proof) (20 ml) over a period of 5 minuteswith vigorous stirring. To the resulting white suspension was addeddistilled water (110 ml) and stirred for 30 minutes. It was warmed toabout 55° C. The resulting homogeneous solution was kept in an oil bathset at 50° C. and slowly cooled down to room temperature for 16 hrs and4° C. for 3 hrs. It was filtered and suction dried for 16 hrs to give11.8 g (˜80% yield) of the lysine salt with homogeneity index of 99.0%as determined by HPLC; mp.: >170° C. with decomposition.

Elemental analysis calculated for C₅₇ H₇₂ N₃ O₂₂ P.8.0 H₂ O: C, 51.62;H, 6.69; N, 3.17; KF (H₂ O), 10.87. Found: 51.76; H, 6.57; N, 3.48; KF(H₂ O), 11.42.

The ethanolamine salt was prepared as follows:

2'-O-(Ethoxycarbonyl)-7-O-phosphonooxymethylpaclitaxel triethylaminesalt (3.0 g, 2.64 mmole) was partitioned between EtOAc (60 ml) and 5%NaHSO₄ (30 ml) with vigorous stirring at 0° C. for 15 minutes. Theaqueous layer was separated and extracted with EtOAc (15 ml). Thecombined EtOAc layer was washed with brine (15 ml), dried over Na₂ SO₄,filtered to give a solution of the free acid (˜2.64 mmole) in EtOAc (˜70ml). To this EtOAc solution at room temperature was added dropwise withvigorous stirring a solution of H₂ NCH₂ CH₂ OH (0.15 ml, 2.64 mmole) inEtOAc (5 mL) over a period of 5 minutes. The resulting suspension wasstirred for an additional 1 hr and then it was filtered, washed withEtOAc (15 ml×2), and dried in vacuo to give 2.6 g of the titleethanolamine salt in 89% yield. HPLC analysis showed homogeneity indexof 97.8%; mp.: >130° C. with decomposition.

Elemental analysis calculated for C₅₃ H₆₅ N₂ O₂₁ P.2.5 H₂ O: C, 55.73;H, 6.18; N, 2.45; KF (H₂ O), 3.94. Found: C, 55.76; H, 6.39; N, 2.45; KF(H₂ O), 6.00.

The arginine salt was prepared as follows:

2'-O-(Ethoxycarbonyl)-7-O-dibenzylphosphonooxymethylpaclitaxel (30.0 g,24.69 mmole) was added portionwise to a suspension of 10% palladium oncarbon (20%, load, 6 g) in EtOH (900 ml, 200 proof) at 0° C. Theresulting suspension was degassed by evacuating air and purging withargon. This process was repeated two additional times. The argon thenwas replaced with hydrogen following the above degassing procedure withvigorous stirring. The resulting mixture was stirred at 0° C. for 2 hrs.The cooling bath was removed and the reaction solution was stirred atambient temperature for additional 24 hrs. The reaction mixture wasdegassed by evacuating hydrogen and purging with argon three timesfollowing the above degassing procedure. It was filtered under argonthrough a pad of Celite. The filtrate was divided into two equalportions and EtOH (190 ml, 200 proof) was added to each portion. To oneportion (˜630 ml) was slowly added a solution of arginine (2.0 g, 0.94eq) in a 2:1 mixture of H₂ O:EtOH (200 proof) (20 ml) over a period of 5minutes with vigorous stirring. To the resulting white suspension wasadded distilled water (100 ml) and stirred for 30 minutes and thenwarmed to about 60° C. It was filtered hot and the filtrate was kept inan oil bath set at 50° C., allowed to cool down to room temperature andkept at room temperature for 2 hrs and at 4° C. for 2 hrs. It wasfiltered and washed with cold 3% H₂ O in EtOH (100 ml) and suction driedfor 16 hrs to give 12.95 g (˜86% yield) of the title arginine salt withhomogeneity index of 96.7%.

This material (12.95 g) was dissolved in a mixture of 15% H₂ O in EtOH(˜700 ml) at 55° C. The solution was cooled down and kept at 30° C. for31/2 hrs, room temperature for 16 hrs, and 4° C. for 3 hrs. Theresulting crystals were filtered, washed with cold 2% H₂ O in EtOH (50ml×2), suction dried for 4 hrs, and then dried in vacuo (1 mmHg) for 16hrs to give 10.2 gs (˜80% yield) of the title arginine salt (homogeneityindex was 98.5%); mp.: >176° C. with decomposition.

Elemental analysis calculated for C₅₇ H₇₂ N₅ O₂₂ P.6.4 H₂ O: C, 51.65;H, 6.45; N, 5.28; KF (H₂ O), 8.7. Found: C, 51.86; H, 6.65; N,5.53; KF(H₂ O), 8.72.

The N-methylglucamine salt was prepared as follows:

2'-O-(Ethoxycarbonyl)-7-O-dibenzylphosphonooxymethylpaclitaxel (30.0 g,24.69 mmole) was added portionwise to a suspension of 10% palladium oncarbon (20% load, 6 g) in EtOH (900 ml, 200 proof) at 0° C. Theresulting suspension was degassed by evacuating air and purging withargon. This process was repeated two additional times. The argon thenwas replaced with hydrogen following the above degassing procedure withvigorous stirring. The resulting mixture was stirred at 0° C. for 2 hrs.The cooling bath was removed and the reaction solution was stirred atambient temperature for additional 24 hrs. The reaction mixture wasdegassed by evacuating hydrogen and purging with argon three timesfollowing the above degassing procedure. It was filtered under argonthrough a pad of Celite. The filtrate was divided into two equalportions and EtOH (190 ml, 200 proof) was added to each portion. To oneportion (˜630 ml) was slowly added a solution of N-methylglucamine (2.24g, 0.94 eq) in a 1:1 mixture of H₂ O:EtOH (200 proof) (20 ml) over aperiod of 5 minutes with vigorous stirring. To the resulting whitesuspension was added distilled water (100 ml) and the suspension wasstirred for 30 minutes and then warmed to about 49° C. The clearhomogeneous solution was kept in an oil bath set at 50° C., allowed tocool down to room temperature and kept at room temperature for 2 hrs andat 4° C. for 11/2 hrs. It was filtered and washed with 3% H₂ O in EtOH(100 ml), suction dried at room temperature for 16 hrs to give 9.65 g(˜64% yield) of the title N-methylglucamine salt with homogeneity indexof 96.4%.

This material (9.65 g) was dissolved in a mixture of 15% H₂ O in EtOH(˜450 ml) at 52° C. Then, the solution was cooled down and kept at 28°C. for 31/2 hrs, room temperature for 16 hrs, and 4° C. for 3 hrs. Theresulting crystals were filtered, washed with cold 2% H₂ O in EtOH (50ml×2), suction dried for 4 hrs; and then dried in vacuo (1 mmHg) for 16hrs to give 7.5 g (˜80% yield) of the title N-methylglucamine salt(homogeneity idex as determined by HPLC was 98.6%); mp.: >154° C. withdecomposition.

Elemental analysis calculated for C₅₈ H₇₅ N₂ O₂₅ P.5.0 H₂ O: C, 52.72;H, 6.48; N, 2.12; KF (H₂ O), 6.82. Found: C, 53.09; H, 6.50; N, 2.08; KF(H₂ O), 7.12.

Example 4 2'-O-(Phosphonooxymethyl)paclitaxel (a) Preparation of2'-O-(methylthiomethyl)-7-O-(triethylsilyl)paclitaxel ##STR55##

To a cooled (0° to -5° C.) solution of 7-O-(triethylsily)paclitaxel(2.46 g; 2.5439 mmol) in dry acetonitrile (100 ml) was addeddimethylsulfide (1.348 g; 1.59 ml; 21.6976 mmol) followed by benzoylperoxide (2.628 g; 10.8488 mmol). The heterogeneous mixture was stirredat 0° C. for 1 h and kept at 5° C. for 18 h. A yellow solution wasobserved. This was evaporated to dryness and purified by silica gelcolumn (eluting with ethyl acetate: hexane, 1:4; 1:3 and 1:2) to givethe title compound (1.0 g, 38%). This was used as such for next step.

MS: [M+H]⁺, 1028; [M+Na]⁺, 1050; [M+K]⁺, 1066

(b) Preparation of 2'-O-(methylthiomethyl)paclitaxel ##STR56##

To a cooled (˜15° C.) solution of the product of step (a) (1.0 g; 0.9737mmol) in dry acetonitrile (30 ml) was added dropwise 0.5N HCl (3 ml).The resulting solution was stirred at -15° C. for 1 h and at 5° C. for18 h. This was diluted with ethyl acetate (20 ml) and washed with cold6% NaHCO₃ solution and brine. It was dried (MgSO₄) and evaporated todryness. This was purified by silica gel plate (methylene chloride: 15%acetonitrile) to give pure title compound (280 mg, 31.4%).

IR (KBr): 3446, 3064, 2940, 1726, 1666, 1582, 1516,1486.

NMR (CDCl₃): δ1.118 (s, 3H), 1.229 (s, 3H), 1.662 (s, 3H), 1.689 (s,3H), 1.871 (s, 3H), 2.209 (s, 3H), 2.450 (s, 3H), 3.800 (d, H), 4.119(d, H), 4.305 (d, H), 4.413 (m, H), 4.563 (d, H), 4.703 (d, H), 4.940(d, H), 4.958 (dd, H), 5.667 (d, H), 5.822 (dd, H), 6.263 (m, 2H), 7.019(d, NH), 7.293-8.127 (m, 15H).

MS: [M+H]⁺, 914; [M+Na]⁺, 936; [M+K]⁺, 952

HRMS: MH⁺ : 914.3394 (calculated=914.3422).

(c) Preparation of 2'-O-(dibenzylphosphonooxymethyl)paclitaxel ##STR57##

To a stirred solution of the product of step (b) (0.89 g; 0.9748 mmol)in dry 1,2-dichloroethane (12 ml) was added powdered 4A molecular sieves(1.0 g) followed by dropwise addition of a solution mixture ofN-iodosuccinimide (0.33 g; 1.4622 mmol) and dibenzyl phosphate (0.41 g;1.4622 mmol) in dry tetrahydrofuran (8 ml). The resulting mixture wasstirred at room temperature for 1 h., then filtered over Celite. Thefiltrate was evaporated to dryness and the red residue was taken up inethyl acetate (50 ml) and washed with cold 6% NaHSO₃, cold 6% NaHCO₃ andbrine. It was dried (MgSO₄) and evaporated to give a foam. This waspurified by silica gel plate (methylene chloride:20% acetonitrile) togive pure product (0.77 g, 69%).

IR (KBr): 3854, 3744, 3362, 3066, 1960, 1722, 1602, 1580.

NMR (CDCl₃): δ1.075 (s, 3H), 1.167 (s, 3H), 1.651 (s, 3H), 1.799 (s,3H), 2.209 (s, 3H), 2.296 (s, 3H), 2.464 (m, H), 3.686 (d, H), 4.121 (d,H), 4.240 (d, H), 4.293 (m, H), 4.808-4.957, (m, 6H), 5.006 (m, H),5.565-5.649 (m, 2H), 6.034 (t, H), 6.194 (3, H), 7.100-8.132, (m, 26H).

MS: [M+H]⁺, 1144; [M+Na]⁺, 1166; [M+K]⁺, 1182

(d) Preparation of 2'-O-(phosphonooxymethyl)paclitaxel ##STR58##

A mixture of the product of step (c) (0.9 g; 0.7874 mmol) and 10% Pd/C(1.0 g) in ethyl acetate (20 ml) was hydrogenated at 60 psi (400 kPa)for 24 h. The reaction mixture was filtered over Celite and the filtrateevaporated to dryness. The residue was purified by silica gel plate(methylene chloride: 40% methanol) to give the title product (0.254 g,33.4%). MP 202°-205° C. (d).

IR (KBr): 3438, 3066, 2942, 1722, 1652, 1602 cm⁻¹.

NMR (acetone-d₆ /D₂ O): δ1.081 (s, 6H), 1.571 (s, 3H), 1.847 (s, 3H),2.115 (s, 3H), 2.357 (s, 3H), 3.707 (d, H), 4.08 (m, 2H), 4.275 (m, H),4.941-5.085 (m, 4H), 5.231 (t, H), 5.430 (d, H), 5.544 (d, H), 5.970 (t,H), 6.376 (s, H), 6.961-8.017 (m, 16H).

MS: [M+Na]⁺, 986; [M+K]⁺, 1002; [M+2Na-H]⁺, 1008; [M+Na+K-H]⁺, 1024;[M+2K-H]⁺, 1040

HRMS: MNa⁺, 986.2955 (Calculated=986.2976).

Example 5 2',7-O-bis(phosphonooxymethyl)paclitaxel sodium salt (a)Preparation of 2',7-O-bis(methylthiomethyl)paclitaxel ##STR59##

Solid benzoyl peroxide (1.995 g, 8 mmol) was added to a stirred solutionof paclitaxel (0.853 g, 1 mmol) and dimethyl sulfide (1.465 g, 20 mmol)acetonitrile (20 mL) at 0° C. The reaction mixture was stirredvigorously at 0° C. for 3 hours. Its progress was monitored by TLC inhexane:ethyl acetate (1:1, v/v), R_(f) paclitaxel =0.24, R_(f) product=0.60. When starting material disappeared (ca. after 3 hrs) the reactionwas quenched by evaporation of solvents to dryness at 25° C. using housevacuum. The dry residue was separated using silica gel column (EMScience, 40-63 μm), 100 mL of dry silica gel, column size: Φ=3/4 in.,solvent system: hexane:ethyl acetate (3:2, v/v), volume of eachfraction: ca. 25 mL. The title compound (0.515 g, 53% yield) wasrecovered from fractions 15 to 19.

MS (FAB/matrix NOBA,NaI KI): [M+H]⁺, m/z 974; [M+Na]⁺, m/z 996; [M+K]⁺,m/z 1012

UV (MeOH): λmax=204 nm, E(1%/1 cm)=243.45; λmax=28 nm, E(1%/1 cm)=313.99

IR (KBr): 3440, 3064, 2926, 1724, 1668, 1602, 1582, 1514, 1484, 1452,1372, 1314, 1266, 1242, 1178, 1142, 1068, 1026, 990, 916, 886, 848, 800,774, 710, 646, 606, 570, 540, 480 cm⁻¹.

¹ H-NMR (CDCl₃) δ: 1.17 (3H, s), 1.20 (3H, s), 1.68 (3H, s), 1.74 (3H,s), 1.84 (H, dd), 2.04 (3H, d), 2.09 (3H, s), 2.15 (3H, s) overlaps with(H, m), 2.37 (H, dd), 2.51 (3H, s), 2.79 (H, ddd), 3.78 (H, d), 4.18 (H,d), 4.28 (H, m), 4.31 (H, d), 4.53-4.74 (4H, two overlapping AB m), 4.93(H,d), 4.95 (H, d), 5.68 (H, d), 5.82 (H, dd), 6.24 (H, dd), 6.54 (H,s), 7.05 (H, d), 7.28-7.59 (10H, overlapping m), 7.57 (H, m), 7.76 (2H,d), 8.09 (2H, d).

(b) Preparation of 2',7-O-bis(dibenzylphosphonooxymethyl)paclitaxel##STR60##

A solution of N-iodosuccinimide, (135 mg, 0.5 mmol) anddibenzylphosphate, (167 mg, 0.5 mmol) in dry tetrahydrofuran (8 mL) wasadded to a mixture of 2',7-O-bis(methylthiomethyl)paclitaxel (198 mg,0.2 mmol) and 5 Å molecular sieves (ca. 200 mg) in methylene chloride(12 mL) at room temperature. The reaction mixture was stirred for 1.5hours, then the molecular sieves were filtered off on celite, washedwith methylene chloride (10 mL) and the solvents were evaporated todryness at room temperature using house vacuum. The residue wasdissolved in ethyl acetate (100 ml) and washed in a separation funnelwith 1% sodium thiosulfate (50 mL), with 0.5m sodium bicarbonate (50mL), and twice with water (2×50 mL). The organic phase was dried overmagnesium sulfate, evaporated to dryness and re-dissolved in ethylacetate (1 mL). The product was precipitated with 50 mL of ethyl ether:hexane (1:1) and washed twice with the same solvent system (2×50 mL). Acrude product (218 mg) was obtained in 74% yield. Purification of thisproduct was performed by loading its methylene chloride solution (3 mL)on silica gel (=101 =3/4 in.×L=1 in.) and eluting the product with 50 mLof methylene chloride:ethyl acetate (3:1) solvent system. The titlecompound (172.7 mg) was obtained in 59.3% yield.

MS (FAB, matrix NOBA/NaI, KI): [M+Na]⁺, m/z 1456; [M+K]⁺, m/z 1472

UV (MeCN): λmax=194 nm, E(1%/1 cm)=1078.36; λmax=228 nm, E(1%/1cm)=311.95

IR (KBr): 3430, 3066, 3032, 2958, 1744, 1726, 1664, 1602, 1582, 1532,1488, 1456, 1372, 1270, 1244, 1158, 1108, 1068, 1016, 1000, 952, 886,800, 776, 738, 698, 604, 498 cm⁻¹.

¹ H-NMR (CDCl₃) δ: 1.12 (3H, s), 1.14 (3H, s), 1.56 (H, m), 1.67 (3H,s), 1.84 (3H, d), 1.90 (H, m), 2.17 (3H, s), 2.29 (3H, s), 2.73 (H, m),3.73 (H, d), 4.08 (H, d), 4.15 (H, m), 4.20 (H, d), 4.77 (H, m), 4.79(H, d), 4.91-5.04 (10H overlapping m), 5.25 (H, dd), 5.38 (H, dd),5.54-5.64 (2H, overlapping m), 5.99 (H, br. dd), 6.25 (H, s), 7.11-7.14(2H, m), 7.24-7.64 (28H, overlapping m), 7.94 (2H, dd), 8.04 (2H, dd),8.30 (H, d).

(c) Preparation of 2',7-O-bis(phosphonooxymethyl)paclitaxel sodium salt##STR61##

A sample of 2',7-O-bis(dibenzylphosphonooxymethyl)paclitaxel (112 mg,0.078 mmol) was dissolved in ethyl acetate (7 ml) and hydrogenated over10% palladium on charcoal (50 mg) at room temperature, 60 PSI (400 kPa),for 2 hours. The catalyst was removed by filtration over Celite. TheCelite was rinsed with ethyl acetate (10 mL). The filtrate was treatedwith solid sodium bicarbonate (20 mg, 3 eq.) and then the solvent wasevaporated to dryness. A dry residue was re-dissolved in 5 mL of water:acetone (4:1, v/v) and purified by C-18 reverse phase columnchromatography (55-105μ C-18, Waters, 50 mL of dry C-18, Φ=3/4 in. inwater: acetone (4:1, v/v). Eluant was monitored on analytical HPLC JonesC-18 column (15 cm, 1 mL/min., λ=230 mn) in acetonitrile:phosphatebuffer pH 6 (50/50, v/v) with the addition of Q12 ion pair cocktail(Regis), Rt=4.7 min. Fractions containing the title product werecombined, acetone was evaporated under house vacuum at 20° C., and thesolution was lyophilized. The title product (44.2 was obtained in 58.8%yield.

MS (FAB,matrix NOBA/NaI, KI): [M+H]⁺, m/z 1118; [M+Na]⁺, m/z 1140

UV (MeCN): λmax=192 nm, E(1%/1 cm)=129.73; λmax=230 nm, E(1%/1 cm)=26.43

IR (KBr): 3430, 3066, 2956, 1724, 1658, 1604, 1582, 1520, 1486, 1452,1374, 1316, 1256, 1152, 1110, 1070, 1026, 966, 914, 802, 772, 710, 538cm⁻¹.

¹ H-NMR (acetone-d₆ /D₂ O) δ: 0.97 (3H, s), 1.02 (3H, S), 1.47 (H, m),1.54 (3H, s), 1.70 (H, m), 1.75 (3H, s), 1.85 (H, m), 2.11 (3H, s), 2.30(3H, s), 2.88 (H, m), 3.64 (H, d), 4.03 (H, m), 4.06 (H, d), 4.16 (H,d), 4.74 (H, m), 4.86 (H, m), 5.11 (H, br. t), 5.22 (H, d), 5.42 (H, d),5.90 (H, br. t), 6.21 (H, s), 7.06 (H, br.t), 7.32-7.69 (10H, ovelappingm), 7.80 (2H, d), 7.93 (2H, d).

Example 6 7-O-methylthiomethylbaccatin III (7-MTM baccatin III)##STR62##

To a solution of 2'-O-ethyloxycarbonyl-7-O-methylthiomethylpaclitaxel(compound of Example 3(b), 27 g, 27.4 mmol) in 100 mL of THF and 500 mLof methanol was added freshly ground K₂ CO₃ (2.7 g, 19 mmol). Thesolution was stirred for 30 minutes and neutralized with IR-120 (H⁺)resin, filtered and concentrated. The crude filtrate was then dissolvedin 200 mL of dichloromethane and stirred for 24 hours withtetrabutylammoniumborohydride (10 g). The solution was diluted withdichloromethane and washed with water, saturated bicarbonate and brine.The organic fraction was then dried over MgSO₄ and concentrated. Theresidue was chromatographed over silica gel (1:1 hexane/ethyl acetate)to give 9.4 g of the title compound (53%) with a melting point of 269°C.

FABMS (NOBA) M+H calcd for C₃₃ H₄₃ SO₁₁ : 647. Found: 647.

IR(KBr) 3474, 1746, 1724, 1712, 1270, 1240, 1070 cm⁻¹

¹ H NMR (CDCl₃, 300 MHz) δ8.08 (d, J=7.1 Hz, 2H), 7.58 (t, J=7.5 Hz,1H), 7.45 (t, J=7.8 Hz, 2H), 6.55 (s, 1H), 4.94 (d, J=8.1 Hz, 1H), 4.83(bq, J=5.1 Hz, 1H), 4.66 (ABq, J=14.7,12.3 Hz, 2H), 4.30 (m, 2H), 4.13(d, J=8.4 Hz, 1H), 3.91 (d, J=6.6 Hz, 1H), 2.79 (m, 1H), 2.27 (s, 3H),2.25 (m, 2H), 2.19 (s, 3H), 2.16 (s, 3H), 2.10 (s, 4H), 1.81 (m, 1H),1.72 (s, 3H), 1.61 (m, 2H), 1.16 (s, 3H), 1.03 (s, 3H).

¹³ C NMR (CDCl₃, 75.5 Hz) δ202.3, 170.8, 169.3, 167.0, 144.2, 132.6,132.1, 130.1, 129.4, 128.6, 83.9, 80.9, 78.7, 75.7, 74.5, 73.9, 67.9,57.6, 47.6, 42.7, 38.3, 26.7, 22.6, 21.0, 20.1, 15.2, 15.0, 10.8.

Example 73'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-furyl)-2'-O-ethyloxycarbonyl-7-O-phosphonooxymethylpaclitaxeltriethanolamine salt (a) Preparation of3'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-furyl)-7-O-methylthiomethylpaclitaxel##STR63##

To a solution of HMDS (0.40 mL, 1.90 mmol) in 15 mL of THF was added asolution of n-BuLi (0.75 mL, 2.5M in hexanes, 1.88 mmol) and stirred 5minutes at -55° C. To this solution was added 7-MTM baccatin III(compound of example 6, 1.03 g, 1.59 mmol) in 10 mL of THF and stirredfor 10 minutes before addition of an 10 mL solution of(3R,4R)-1-(t-butyloxycarbonyl)-4-(2-furyl)-3-(triethylsilyloxy)-2-azetidinone(883 mg, 2.40 mmol). The cold bath was removed and replaced with a 0° C.bath and the reaction mixture was stirred for 30 minutes. The solutionwas diluted with ethyl acetate and washed with saturated NH₄ Clsolution, dried over MgSO₄ and concentrated. The residue waschromatographed over silica gel (2.5:1 hexane/ethyl acetate) to give 1.5g of the coupling product3'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-furyl)-7-O-methylthiomethyl-2'-O-triethylsilylpaclitaxel(93%).

FABMS (NOBA) M+Na calcd for C₅₀ H₇₁ NSSiO₁₆ : 1036. Found: 1036.

IR(film) 3446 (s), 1720, 1368, 1242, 1166, 1144, 1124, 1066 cm⁻¹

¹ H NMR (CDCl₃, 300 MHz) δ8.07 (d, J=7.2 Hz, 2H), 7.56 (m, 1H), 7.46 (t,J=7.5 Hz, 2H), 7.36 (m, 1H), 6.56 (s, 1H), 6.33 (m, 1H), 6.20 (m, 2H),5.67 (d, J=6.9 Hz, 1H), 5.29 (bs, 2H), 4.94 (d, J=7.8 Hz, 1H), 4.75 (s,1H), 4.65 (s, 2H), 4.28 (m, 2H), 4.16 (d, J=8.1 Hz, 1H), 3.89 (d, J=6.9Hz, 1H), 2.80 (m, 1H), 2.46 (s, 3H), 2.37 (m, 1H), 2.22 (m, 1H), 2.16(s, 3H), 2.10 (s, 3H), 2.04 (s, 3H), 1.84 (m, 1H), 1.74 (s, 3H), 1.65(m, 1H), 1.33 (s, 9H), 1.20 (s, 3H), 1.19 (s, 3H), 0.81 (t, J=7.8 Hz,9H), 0.47 (m, 6H).

¹³ C NMR (CDCl₃, 75.5 Hz) δ202.0, 171.2, 170.3, 169.3, 167.1, 155.3,152.0, 141.9, 141.0, 133.6, 132.9, 130.2, 129.2, 128.7, 110.7, 107.3,84.0, 81.1, 80.2, 78.7, 76.1, 75.7, 74.7, 74.1, 72.4, 71.1, 57.4, 52.8,47.1, 43.3, 35.2, 33.0, 28.1, 26.3, 22.9, 21.2, 21.0, 15.0, 14.5, 10.9,6.5, 4.3.

To a solution of the 2'-triethylsilyl ether obtained above (330 mg, 0.32mmol) in 7 mL of THF was added tetrabutylammonium fluoride (0.35 mL,1.0M in THF, 0.35 mmol) and stirred 10 minutes. The solution was dilutedwith ethyl acetate and washed with brine, dried over MgSO₄ andconcentrated and the residue was chromatographed over silica gel (2:1hexane/ethyl acetate) to give 301 mg of the title compound (95%).

FABMS (NOBA) M+H calcd for C₄₅ H₅₉ NO₁₆ S: 900. Found: 900.

IR(film) 3442, 1720, 1242, 1066, 1026 cm⁻¹

¹ H NMR (CDCl₃, 300 MHz) δ8.07 (d, J=7.3 Hz, 2H), 7.57 (t, J=7.3 Hz,1H), 7.45 (t, J=7.8 Hz, 2H), 7.38 (s, 1H), 6.53 (s, 1H), 6.34 (d, J=3.2Hz, 1H), 6.29 (d, J=3.2 Hz, 1H), 6.17 (t, J=8.1 Hz, 1H), 5.65 (d, J=6.9Hz, 1H), 5.29 (m, 2H), 4.92 (d, J=8.0 Hz, 1H), 4.70 (m, 1H), 4.64 (d,J=4.6 Hz, 2H), 4.29 (m, 2H), 4.14 (d, J=8.3 Hz, 1H), 3.86 (d, J=6.8 Hz,1H), 3.37(d, J=5.8 Hz, 1H), 2.77 (m, 1H), 2.38 (s, 3H), 2.32 (m, 2H),2.16 (s, 3H), 2.10 (s, 3H), 2.02 (s, 3H), 1.77 (m, 3H), 1.73 (s, 3H),1.33 (s, 9H), 1.17 (s, 3H), 1.12 (s, 3H).

¹³ C NMR (CDCl₃, 75.5 Hz) δ202.0, 172.6, 170.3, 169.2, 167.0, 155.2,151.3, 142.4, 140.4, 133.7, 133.2, 130.2, 129.1, 128.7, 110.7, 107.4,83.9, 81.2, 80.5, 78.6, 76.5, 76.1, 75.4, 74.6, 74.0, 72.5, 71.8, 57.4,51.7, 47.2, 43.2, 35.2, 32.8, 28.1, 26.4, 22.6, 20.9, 15.2, 14.6, 10.9,8.3.

(b) Preparation of3'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-furyl)-2'-O-ethyloxycarbonyl-7-O-methylthiomethylpaclitaxel##STR64##

To a solution of the product of step (a) (864 mg, 0.96 mmol) in 50 mL ofdichloromethane at 0° C. was added diisopropylethyl amine (2.0 mL, 11.5mmol) and ethyl chloroformate (0.50 mL, 5.25 mmol) and stirred for 4hours. The solution was diluted with dichloromethane and washed withsaturated bicarbonate and dried over MgSO₄ and concentrated. The residuewas chromatographed over silica gel (1:1 hexane/ethyl acetate) to give884 mg of the 2' ethyl carbonate title compound (95%).

FABMS (NOBA) M+H calcd for C₄₉ H₆₂ NO₁₈ S 972.3688. Found: 972.3654.

IR(film) 1752, 1720, 1370, 1244, 1196, 1176, 1064 cm⁻¹

¹ H NMR (CDCl₃, 300 MHz) δ8.09 (d, J=7.8 Hz, 2H), 7.57 (t, J=7.5 Hz,1H), 7.46 (t, J=7.8 Hz, 2H), 7.38 (s, 1H), 6.55 (S, 1H), 6.35 (m, 1H),6.27 (m, 1H), 6.22 (t, J=7.8 Hz, 1H), 5.67 (d, J=7.2 Hz, 1H), 5.51 (d,J=9.9 Hz, 1H), 5.34 (d, J=2.4 Hz, 1H), 5.25 (d, J=10.2 Hz, 1H), 4.95 (d,J=8.1 Hz, 1H), 4.65 (s, 2H), 4.30 (m, 2H), 4.22 (m, 2H), 3.88 (d, J=7.2Hz, 1H), 2.81 (m, 1H), 2.41 (s, 3H), 2.36-2.21 (m, 2H), 2.16 (s, 3H),2.11 (s, 3H), 2.09 (s, 3H), 1.83 (m, 1H), 1.74 (s, 3H), 1.67 (s, 1H),1.59 (s, 1H), 1.34 (s, 9H), 1.29 (t, J=7.2 Hz, 3H), 1.20 (s, 3H), 1.18(s, 3H).

¹³ C NMR (CDCl₃, 75.5 Hz) δ202.1, 169.9, 169.1, 167.6, 167.0, 154.0,150.1, 142.6, 141.0, 133.6, 132.9, 130.2, 129.2, 128.7, 110.7, 107.5,83.9, 81.1, 80.7, 78.7, 76.0, 75.7, 75.1, 74.7, 74.2, 71.8, 65.1, 57.4,49.7, 47.1, 43.2, 35.0, 33.0, 28.1, 26.3, 22.6, 21.1, 20.9, 15.1, 14.5,14.1, 10.9.

(c) Preparation of3'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-furyl)-2'-O-ethyloxycarbonyl-7-O-dibenzylphosphonooxymethylpaclitaxel##STR65##

To a solution of the product of step (b) (230 mg, 0.236 mmol) in 10 mLof anhydrous THF was added 300 mg of 4A sieves, dibenzylphosphate (270mg, 0.98 mmol) and recrystallized NIS (62 mg, 0.28 mmol). To thissolution was added silver trifluoromethanesulfonate (45 mg, 0.17 mmol)and the solution stirred for 3 hours. The solution was filtered throughCelite and diluted with ethyl acetate and washed with 10% NaS₂ O₈,sautruated bicarbonate, and brine, dried over MgSO₄ and concentrated.The residue was chromatographed over silica gel (15%acetonitrile/chloroform) to give 219 mg of the dibenzyl phosphate titlecompound (77%).

FABMS (NOBA) M+Na calcd for C₆₁ H₇₂ NPO₂₂ Na 1224. Found: 1224.

IR(film) 3422 (br), 1750, 1722, 1370, 1244, 1160, 1036, 1016, 1000, 976,944 cm⁻¹

¹ H NMR (CDCl₃, 300 MHz) δ8.08 (d, J=6.9 Hz, 2H), 7.58 (t, J=7.2 Hz,1H), 7.46 (t, J=7.8 Hz, 2H), 7.39 (s, 1H), 7.31 (m, 10), 6.35 (m, 2H),6.28 (s, 1H), 6.21 (t, J=7.8 Hz, 1H), 5.64 (d, J=6.9 Hz, 1H), 5.50 (d,J=10.5 Hz, 1H), 5.39 (d, J=6.6 Hz, 1H), 5.32 (d, J=2.4 Hz, 1H), 5.25 (d,J=9.9 Hz, 1H), 5.01 (dd, J=8.1, 6.3 Hz, 5H), 4.86 (d, J=8.4 Hz, 1H),4.29-4.09 (m, 4H), 3.85 (d, J=6.9 Hz, 1H), 2.77 (m, 1H), 2.40 (s, 3H),2.30 (m, 2H), 2.16 (s, 3H), 1.99 (s, 3H), 1.94 (m, 1H), 1.70 (s, 3H),1.67 (s, 1H), 1.54 (s, 1H), 1.34 (s, 9H), 1.28 (t, J=7.2 Hz, 3H), 1.20(s, 3H), 1.17 (s, 3H).

¹³ C NMR (CDCl₃, 75.5 Hz) δ201.8, 169.9, 169.2, 167.7, 167.0, 155.1,154.0, 150.0, 142.74, 141.1, 133.7, 132.9, 130.2, 129.1, 128.7, 128.5,128.4, 128.0, 110.7, 107.6, 93.8, 84.1, 81.6, 80.8, 80.7, 78.8, 76.3,75.1, 74.6, 71.8, 69.3, 69.2, 65.1, 57.0, 49.7, 46.7, 43.2, 35.0, 28.1,26.4, 22.6, 21.2, 20.8, 14.6, 14.1, 10.5.

(d) Preparation of3'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-furyl)-2'-O-ethyloxycarbonyl-7-O-phosphonooxymethylpaclitaxeltriethanolamine salt ##STR66##

To a solution of the product of step (c) (311 mg, 0.259 mmol) in 25 mLof ethyl acetate was added 60 mg of Pd on carbon (10%) and the solutionstirred under an atmosphere of H₂ for 30 minutes. The catalyst wasremoved by filtratation through Celite and the filtrate concentrated invacuo. The residue was dissolved in 3 mL of ethyl acetate andtriethananolamine added (2.3 mL, 0.1M in ethyl acetate, 0.23 mmol). Thesolution was concentrated and the residue was chromatographed over C₁₈(40% acetonitrile/water) and lyophilized to give 205 mg of the phosphatetriethanolamine salt (67%).

FABMS (NOBA) M+Na calcd for C₄₇ H₆₀ HPO₂₂ Na 1044. Found: 1044.

IR(film) 3432 (br), 1752, 1722, 1372, 1246, 1158, 1108, 1096, 1070, 1002cm⁻¹

¹ H NMR (d6 acetone/D₂ O, 300 MHz) δ8.09 (d, J=7.2 Hz, 2H), 7.62 (m,2H), 7.52 (t, J=7.5 Hz, 2H), 6.48 (d, J=3.3 Hz, 1H), 6.42 (m, 2H), 6.16(t, J=8.7 Hz, 1H), 5.65 (d, J=6.9 Hz, 1H), 5.46 (d, J=3.6 Hz, 1H), 5.30(d, J=3.6 Hz, 1H), 5.17 (bs, 1H), 5.01 (bd, J=9.0 Hz, 1H), 4.19 (bs,1H), 4.18 (m, 5H), 3.95 (m, 4H), 3.87 (d, J=6.9 Hz, 1H), 3.68 (s, 10H),3.50 (bt, J=4.8 Hz, 4H), 2.95 (m, 1H), 2.44 (s, 3H), 2.41 (m, 2H), 2.16(s, 3H), 1.99 (s, 3H), 1.94 (m, 1H), 1.68 (s, 3H), 1.34 (s, 9H), 1.24(t, J=6.9 Hz, 3H), 1.17 (s, 6H).

Example 83'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-thienyl)-2'-O-ethyloxycarbonyl-7-O-phosphonooxymethylpaclitaxeltriethanolamine salt (a) Preparation of3'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-thienyl)-7-O-methylthiomethylpaclitaxel##STR67##

To a solution of HMDS (0.5 mL, 2.4 mmol) in 18 mL of THF at -55° C. wasadded n-BuLi (0.85 mL, 2.5M in hexanes, 2.1 mmol). After 10 minutes7-MTM baccatin III (1.15 g, 1.78 mmol) in 18 mL of THF was addeddropwise and stirred in the cold for 10 minutes.(±)cis-1-(t-Butyloxycarbonyl)-4-(2-thienyl)-3-(triethylsilyloxy)-2-azetidinone(2.80 g, 7.3 mmol) in 18 mL of THF was added and the cold bath allowedto slowly warm to 0° C. over 30 minutes. The solution was diluted withethyl acetate and washed with saturated NH₄ Cl solution, dried overMgSO₄ and concentrated. The residue was chromatographed over silica gel(5:1 hexane/ethyl acetate) to give 1.87 g of recovered lactam (3:1hexane/ethyl acetate) to give 1.44 g of the coupling product3'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-thienyl)-7-O-methylthiomethyl-2'-O-triethylsilylpaclitaxel(78%).

FABMS (NOBA) M+Na calcd for C₅₁ H₇₁ NO₁₅ S₂ SiNa 1052. Found: 1052.

IR(film) 3442 (br), 1720, 1490, 1368, 1270, 1242, 1162, 1110, 1064,1024, 984, 754 cm⁻¹

¹ H NMR (CDCl₃, 300 MHz) δ8.09 (d, J=7.2 Hz, 2H), 7.57 (t, J=7.6 Hz,1H), 7.47 (t, J=7.8 Hz, 2H), 7.22 (m, 1H), 6.95 (m, 2H), 6.55 (s, 1H),6.21 (t, J=9.3 Hz, 1H), 5.68 (d, J=6.9 Hz, 1H), 5.49 (bd, 1H), 5.39 (bd,J=9.6 Hz, 1H), 4.94 (d, J=7.8 Hz, 1H), 4.65 (s, 2H), 4.57 (s, 1H), 4.28(m, 2H), 4.17 (d, J=8.4 Hz, 1H), 3.88 (d, J=6.9 Hz, 1H), 2.80 (m, 1H),2.46 (s, 3H), 2.37 (m, 1H), 2.20 (m, 1H), 2.17 (s, 3H), 2.10 (s, 3H),2.03 (s, 3H), 1.84 (m, 1H), 1.74 (s, 3H), 1.68 (s, 1H), 1.62 (s, 1H),1.31 (s, 9H), 1.20 (s, 6H), 0.84 (t, J=7.8 Hz, 9H), 0.50 (m, 6H).

¹³ C NMR (CDCl₃, 75.5 Hz) δ201.9, 171.1, 170.7, 170.1, 169.3, 167.0,155.1, 142.8, 140.9, 133.6, 132.9, 130.2, 129.2, 128.7, 126.9, 124.6,83.9, 81.2, 80.1, 78.8, 77.4, 76.0, 75.7, 75.2, 74.8, 74.1, 71.3, 57.4,53.8, 47.0, 43.3, 35.3, 33.3, 28.1, 26.3, 23.0, 21.3, 20.9, 14.9, 14.4,10.9, 6.6, 4.5.

To a solution of the 2'-triethylsilyl ether obtained above (1.41 g, 1.37mmol) in 14 mL of THF was added tetrabutylammonium fluoride (1.4 mL,1.0M in THF, 1.40 mmol). The solution was stirred for 30 minutes,diluted with ethyl acetate and washed with brine, dried over MgSO₄ andconcentrated. The residue was chromatographed over silica gel (1:1hexane/ethyl acetate) to give 1.16 g of the title compound (92%).

FABMS (NOBA) M+Na calcd for C₄₅ H₅₇ NO₁₅ S₂ Na 938. Found: 938.

IR(film) 3440 (br), 1720, 1368, 1242, 1168, 1106, 1066, 710 cm⁻¹

¹ H NMR (CDCl₃, 300 MHz) δ8.08 (d, J=7.2 Hz, 2H), 7.59 (m, 1H), 7.47 (t,J=7.8 Hz, 2H), 7.24 (m, 1H), 7.07 (m, 1H), 6.99 (m, 1H), 6.53 (s, 1H),6.18 (t, J=8.1 Hz, 1H), 5.66 (d, J=6.9 Hz, 1H), 5.49 (d, J=9.6 Hz, 1H),5.32 (d, J=9.6 Hz, 1H), 4.92 (d, J=7.8 Hz, 1H), 4.63 (m, 3H), 4.28 (m,2H), 4.15 (d, J=8.4 Hz, 1H), 3.86 (d, J=6.9 Hz, 1H), 3.47 (d, J=5.4 Hz,1H), 2.78 (m, 1H), 2.36 (s, 3H), 2.34 (, 2H), 2.17 (s, 3H), 2.10 (s,3H), 2.00 (s, 3H), 1.83 (m, 1H), 1.74 (s, 3H), 1.72 (s, 1H), 1.61 (s,1H), 1.33 (s, 9H), 1.21 (s, 3H), 1.18 (s, 3H).

¹³ C NMR (CDCl₃, 75.5 Hz) δ201.9,172.3, 170.3, 169.2, 167.0, 154.0,141.5, 140.2, 133.7, 133.3, 130.2, 129.1, 128.7, 127.0, 125.4, 125.4,83.9, 81.3, 80.4, 78.6, 76.1, 75.4, 74.5, 74.0, 73.4, 72.5, 57.5, 52.8,47.2, 43.2, 35.3, 32.9, 28.2, 26.4, 22.6, 20.9, 15.1, 14.7, 10.8.

(b) Preparation of3'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-thienyl)-2'-O-ethyloxycarbonyl-7-O-methylthiomethylpaclitaxel##STR68##

To a solution of the product of step (a) (621 mg, 0.677 mmol) in 35 mLof dichloromethane at 0° C. was added diisopropylethyl amine (1.20 mL,6.89 mmol) and ethyl chloroformate (0.35 mL, 3.7 mmol) and stirred for 1hour. The cold bath was removed and the solution stirred for 2 hours andwas diluted with dichloromethane and was washed with saturatedbicarbonate and dried over MgSO₄ and concentrated. The residue waschromatographed over silica gel (1:1 hexane/ethyl acetate) to give 528mg of the title compound (79%).

FABMS (NOBA) M+Na calcd for C₄₈ H₆₁ NO₁₇ S₂ Na 1010. Found: 1010.

IR(film) 3510, 3440, 1752, 1720, 1370, 1244, 1198, 1170, 1026, 988, 756cm⁻¹

¹ H NMR (CDCl₃, 300 MHz) δ8.09 (d, J=7.2 Hz, 2H), 7.58 (m, 1H), 7.48 (t,J=7.8 Hz, 2H), 7.26 (m, 1H), 6.99 (, 2H), 6.55 (s, 1H), 6.23 (t, J=9.0Hz, 1H), 5.68 (d, J=6.9 Hz, 2H), 5.33 (d, J=9.9 Hz, 1H), 5.25 (d, J=2.4Hz, 1H), 4.94 (d, J=7.8 Hz, 1H), 4.65 (s, 2H), 4.33-4.08 (m, 5H), 3.88(d, J=6.9 Hz, 1H), 2.80 (m, 1H), 2.40 (s, 3H), 2.40-2.20 (m, 2H), 2.16(s, 3H), 2.11 (s, 3H), 2.07 (s, 3H), 1.83 (m, 1H), 1.74 (s, 3H), 1.69(s, 1H), 1.60 (s, 1H), 1.33 (s, 9H), 1.31 (t, J=7.2 Hz, 9H), 1.20 (s,3H), 1.19 (s, 3H).

¹³ C NMR (CDCl₃, 75.5 Hz) δ202.0, 169.7, 169.1, 167.5, 167.1, 154.0,140.9, 133.6, 132.9, 130.2, 129.2, 128.7, 127.2, 125.4, 125.3, 83.9,81.2, 80.6, 78.8, 76.9, 76.0, 75.7, 74.7, 74.2, 72.8, 72.0, 65.2, 57.4,50.9, 47.1, 43.3, 35.1, 33.0, 28.1, 26.4, 22.7, 21.2, 20.9, 15.1, 14.5,14.1, 10.9.

(c) Preparation of3'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-thienyl)-2'-O-ethyloxycarbonyl-7-O-dibenzylphosphonooxymethylpaclitaxel##STR69##

To a solution of the product of step (b) (516 mg, 0.522 mmol) in 15 mLof anhydrous THF was added 530 mg of 4A sieves, dibenzylphosphate (576mg, 2.09 mmol) and recrystalized NIS (136 mg, 0.604 mmol). To thissolution was added silver trifluoromethanesulfonate (50 mg, 0.194 mmol)and the solution stirred for 1 hour. The solution was filtered throughCelite and diluted with ethyl acetate and washed with 10% NaS₂ O₈,saturated bicarbonate and brine, dried over MgSO₄ and concentrated. Theresidue was chromatographed over silica gel (15%acetonitrile/chloroform) to give 535 mg of the title compound (84%).

FABMS (NOBA) M+Na calcd for C₆₁ H₇₂ NO₂₁ PSNa 1240. Found: 1240.

IR(film) 3424 (br), 1750, 1722, 1370, 1244, 1016, 1000, 944 cm⁻¹ ¹ H NMR(CDCl₃, 300 MHz) δ8.08 (d, J=7.0 Hz, 2H), 7.58 (m, 1H), 7.47 (t, J=7.5Hz, 2H), 7.28 (m, 11H), 6.99 (m, 2H), 6.33 (s, 1H), 6.22 (t, J=7.8 Hz,1H), 5.66 (m, 2H), 5.39 (t, J=6.6 Hz, 1H), 5.34 (d, J=12 Hz, 1H), 5.22(d, J=2.4 Hz, 1H), 5.01 (dd, J=8.1, 6.0 Hz, 5H), 4.86 (d, J=7.8 Hz, 1H),4.29-4.08 (m, 5H), 3.85 (d, J=6.6 Hz, 1H), 2.76 (m, 1H), 2.39 (s, 3H),2.35-2.18 (m, 2H), 2.16 (s, 3H), 1.97 (s, 4H), 1.69 (s, 4H), 1.33 (s,9H), 1.30 (t, J=7.2 Hz, 3H), 1.20 (s, 3H), 1.17 (s, 3H).

¹³ C NMR (CDCl₃, 75.5 Hz) δ197.4, 165.4, 164.9, 163.3, 162.7, 150.6,149.7, 136.7, 136.0, 129.4, 128.6, 125.9, 124.7, 124.3, 124.2, 124.1,123.6, 122.9, 121.1, 121.0, 89.4, 79.8, 77.3, 76.5, 76.3, 74.4, 72.0,70.7, 70.3, 67.7, 64.9, 64.9, 60.9, 52.7, 46.5, 42.3, 38.9, 30.7, 23.8,22.0, 18.3, 17.0, 16.4, 10.3, 9.8, 6.2.

(d) Preparation of3'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-thienyl)-2'-O-ethyloxycarbonyl-7-O-phosphonooxymethylpaclitaxeltriethanolamine salt ##STR70##

To a solution of the product of step (c) (512 mg, 0.42 mmol) in 30 mL ofethyl acetate was added 53 mg of Pd on carbon (10%) and the solutionstirred under an atmosphere of H₂ for 3 hours. The catalyst was removedby filtratation through Celite and the filtrate concentrated in vacuo.The residue was dissolved in 2 mL of ethyl acetate and triethananolamineadded (4.0 mL, 0.1M in ethyl acetate, 0.40 mmol). The solution wasconcentrated and the residue was chromatographed over C₁₈ (40%acetonitrile/water) and lyophilized to give 280 mg of the phosphatetriethanolamine salt (56%). HPLC analysis showed the purity of the saltto be 96%.

FABMS (NOBA) M+Na calcd for C₄₇ H₆₀ NO₂₁ PS 1060. Found: 1060.

IR(KBr) 3422 (br), 1750, 1720, 1372, 1246, 1162, 1096, 1068, 1000 cm⁻¹

¹ H NMR (d₆ acetone/D₂ O, 300 MHz) δ8.06 (d, J=7.2 Hz, 2H), 7.63 (t,J=7.2 Hz, 1H), 7.52 (t, J=7.8 Hz, 2H), 7.38 (d, J=4.2 Hz, 1H), 7.16 (d,J=3.5 Hz, 1H), 7.01 (dd, J=5.1, 3.6 Hz, 1H), 6.37 (s, 1H), 6.11 (t,J=8.7 Hz, 1H), 5.61 (d, J=6.9 Hz, 1H), 5.60 (s, 1H), 5.26 (d, J=4.5 Hz,1H), 5.14 (t, J=6.6 Hz, 1H), 5.00 (d, J=8.4 Hz, 1H), 4.86 (dd, J=12.0,6.3 Hz, 1H), 4.17 (m, 5H), 4.00 (s, 7H), 3.92 (t, J=4.8 Hz, 6H), 3.84(d, J=6.9 Hz, 1H), 3.48 (t, J=5.4 Hz, 6H), 2.94 (m, 1H), 2.42 (s, 3H),2.36 (m, 1H), 2.27 (m, 1H), 2.15 (s, 3H), 1.95 (s, 4H), 1.66 (s, 3H),1.30 (s, 9H), 1.23 (t, J=7.2 Hz, 3H), 1.14 (s, 6H).

Example 910-Desacetyl-3'-N-desbenzoyl-3'-N-(t-butyloxycarbonyl)-10-O-(phosphonooxymethyl)paclitaxel(a) Preparation of10-desacetyl-10-O-benzyloxycarbonyl-7-O-triethylsilylbaccatin III##STR71##

To a dry flask under an argon atmosphere containing7-O-triethylsilyl-10-desacetyl baccatin III (2.093 g, 3.177 mmol) wasadded dry THF (30 mL) and cooled to -70° C. To this was added 1.6Mn-butyllithium (2.38mL, 3.81 mmol) in a dropwise fashion. After stirringfor 15 min, benzyl chloroformate (0.91 mL, 6.35 mmol) was addeddropwise. The resulting mixture was stirred for 3 h with gradual warmingto ambient temperature. The reaction was quenched with 25 mL of sat. NH₄Cl, washed with brine, and dried with MgSO₄. Flash chromatography(silica gel, 30-45% ethyl acetate/hexane) furnished 2.24 g (89%) of thetitle compound as a white foam.

¹ H NMR (300 MHz, CDCl₃) δ8.10 (d, J=8.0, 2H); 7.63-7.58 (m, 1H) 7.47(t, J=8.0, 2H); 7.41-7.26 (m, 5H); 6.29 (s, 1H); 5.61 (d, J=7.0, 1H);5.20 (q, J=12.2, 2H); 4.96 (d, J=9.0, 1H); 4.87-4.84 (m, 1H); 4.48 (dd,J=6.7, J=10.4, 1H); 4.30 (d, J=8.5, 1H); 4.14 (d, J=8.5, 1H); 3.84 (d,J=7.0, 1H); 2.58-2.48 (m, 1H); 2.29 (m, 4H); 2.20 (s, 3H); 2.03 (d,J=5.0, 1H); 1.92-1.83 (m, 1H); 1.68 (s, 3H); 1.17 (s, 3H); 1.04 (s, 3H);0.91 (t, J=7.5, 9H); 0.57 (q, J=7.4, 6H).

(b) Preparation of10-desacetyl-10-O-benzyloxycarbonyl-3'-N-debenzoyl-3'-N-(t-butyloxycarbonyl)-2',7-bis-O-triethylsilylpaclitaxel##STR72##

To a dry flask containing the product of step (a) (3.50 g, 4.42 mmol)was added a small amount of toluene and the solution was thenconcentrated under vacuum. This flask was placed under an argonatmosphere and 100 mL of dry THF was added. The flask was cooled to -70°C. and 1.0M lithium hexamethyldisilazide (6.19 mL, 6.19 mmol) was addedin a dropwise fashion. After stirring for 20 min, a solution of(3R,4S)-1-(t-butyloxycarbonyl)-4-phenyl-3-triethylsilyloxy-2-azetidinone(2.58 g, 7.07 mmol) in 10 mL dry THF was added dropwise. The reactionmixture was stirred for 3.5 h, gradually warming to ambient temperature.It was then quenched with 70 mL of sat. NH₄ Cl, washed with brine anddried with MgSO₄. Flash chromatography (silica gel, 5-15% ethylacetate/hexanes) provided 5.12 g (99%,) of the title compound as a whitefoam.

¹ H NMR (300MHz, CDCL₃) δ8.11 (d, J=8.0, 2H); 7.60-7.58 (m, 1H); 7.48(t, J=8.0, 2H); 7.24-7.26 (m, 10H); 6.32-6.26 (m, 2H); 5.69 (d, J=7.0,1H); 5.47 (bd, J=9.7, 1H); 5.31-5.10 (m, 3H); 4.94 (d, J=8.5, 1H); 4.56(s, 1H); 4.46 (dd, J=6.9, J=10.6, 1H); 4.31 (d, J=8.3, 1H); 4.17 (d,J=8.3, 1H); 3.81 (d, J=7.0, 1H); 2.53 (s, 3H); 2.48-2.33 (m, 1H);2.22-2.17 (m, 1H); 2.09 (s, 3H); 1.95-1.86 (m, 1H); 1.70 (s, 3H); 1.65(s, 1H); 1.52 (s, 1H); 1.30 (s, 9H); 1.26-1.19 (m, 6H); 0.94-0.87 (m.9H); 0.80-0.75 (m, 9H); 0.61-0.53 (m, 6H); 0.48-0.30 (m, 6H).

(c) Preparation of10-desacetyl-3'-N-debenzoyl-3'-N-(t-butyloxycarbonyl)-7-O-triethylsilylpaclitaxel##STR73##

The product of step (b) (5.12 g, 4.40 mmol) was dissolved into 100 mL ofethyl acetate, transferred to a Parr bottle and placed under a blanketof argon. To this was added 10% palladium on carbon (2.4 g) and thereaction mixtre was placed on a Parr hydrogenation apparatus (55 psi)for a period of 8 h. The reaction mixture was filtered through a plug ofCelite and concentrated. Flash chromatography (silica gel, 15-20% ethylacetate/hexane) provided 3.24 g (79%) of the title compound as a whitefoam. Hydrolysis of the 2'-triethylsilyl group of the product of step(b) was a result of trace acidic residues in the Parr equipment.

¹ H NMR (300 MHz, CDCl₃) δ8.10 (d,J=8.0, 2H); 7.63-7.58 (m, 1H); 7.49(d, J=8.0, 2H); 7.39-7.26 (m. 5H); 6.27-6.17 (m, 1H); 5.64 (d, J=7.2);5.42 (d, J=9.4, 1H); 5.28-5.25 (m, 1H); 5.12 (s, 1H); 4.92 (d, J=8.6,1H); 4.62 (bs, 1H); 4.38-4.28 (m, 3H); 4.17 (d, J=8.5, 1H); 3.85 (d,J=6.7, 1H); 3.36 (d, J=5.3, 1H); 2.49-2.40 (m, 1H); 2.36 (s, 3H); 2.25(bd, J=8.7, 2H); 1.99-1.91 (m, 1H); 1.85 (s, 3H); 1.74 (s, 3H); 1.69 (s,1H), 1.67 (s, 1H); 1.35 (s, 9H); 1.22 (s, 3H); 1.11 (s, 3H); 0.93 (t,J=7.5 9H); 0.61-0.49 (m. 6H).

(d) Preparation of10-desacetyl-2'-O-benzyloxycarbonyl-3'-N-debenzoyl-3'-N-(t-butyloxycarbonyl)-7-O-triethylsilylpaclitaxel##STR74##

To a flask containing the product of step (c) (3.24 g, 3.51 mmol) wasadded 30 mL of dry dichloromethane. The flask was placed under argon andcooled to 0° C. N,N-diisopropylethylamine (1.22 mL, 7.02 mmol) was addedto the reaction mixture, followed by addition of benzyl chloroformate(1.00 mL, 7.02 mmol) in a dropwise manner. After 15 min, the coolingbath was removed and the reaction allowed to stir at ambient temperaturefor 7 h. The mixture was quenched with 30 mL sat. NH₄ Cl, washed withbrine and dried with MgSO₄. Flash chromatography (silica gel, 7-20%ethyl acetate/hexane) provided 3.24 g (89%) of the title compound as awhite solid.

¹ H NMR (300 MHz, CDCl₃) δ8.10 (d, J=8.0, 2H); 7.62-7.57 (m, 1H); 7.48(t, J=8.0, 2H); 7.40-7.26 (m, 10H); 6.33-6.27 (m, 1H); 5.66 (d, J=7.0,1H); 5.49-5.42 (m, 2H); 5.31 (s, 1H); 5.22-5.13 (m , 3H); 4.93 (d,J-9.4, 1H); 4.38 (dd, J=6.5, J=10.7, 1H); 4.34-4.28 (m, 2H); 4.18 (dJ=8.3, 1H); 3.90 (d, J=6.7, 1H); 2.52-2.30 (m, 4H); 2.24-2.20 (m, 1H);1.97-1.87 (m, 3H); 1.74 (s, 3H); 1.59 (s, 3H); 1.32 (s, 9H); 1.26, (s,3H); 1.11 (s, 3H); 0.96-0.88 (m, 9H); 0.61-0.48 (m, 6H).

(e) Preparation of10-desacetyl-2'-O-benzyloxycarbonyl-3'-N-debenzoyl-3'-N-(t-butyloxycarbonyl)-10-O-(dibenzylphosphonooxymethyl)-7-triethylsilylpaclitaxel##STR75##

The product of step (d) was dissolved into 13.5 mL (54%) of DMSO, 8.75mL (35%) acetic anhydride and 2.75 mL (11%) glacial acetic acid andplaced under an atmosphere of argon. The reaction mixture stirred for 56h, after which it was diluted with ethyl acetate to a volumn of 60 mL.The solution was washed with sat. NaHCO₃ until neutral by pH paper andthen washed with brine. The organic fraction was dried with MgSO₄ andconcentrated. Flash chromatography with 15-20% EtOAc/hexane provided3.12 g of crude white foam with the desired thiomethyl acetal product(i.e.10-desacetyl-2'-O-benzyloxycarbonyl-3'-N-debenzoyl-3'-N-(t-butyloxycarbonyl)-10-O-(methylthiomethyl)-7-O-triethylsilylpaclitaxelaccounting for 70% of the material by NMR.

The above crude mixture (3.12 g) was then dissolved in1,2-dichloroethane (61 mL) and placed under a blanket of argon. 4 Åpowdered molecular sieves (3.12 g) were added and the resultingheterogeneous mixture was stirred vigorously. To this was added asolution of recrystallized N-iodosuccinimide (0.830 g, 3.69 mmol) anddibenzyl phosphate (1.027 g, 3.69 mmol) in dry THF (46 mL) via cannula.The resulting mixture was stirred for 5 h, filtered through a plug ofCelite, and diluted to a volume of 250 mL with ethyl acetate It waswashed with (2×125 mL) of cold 2% NaHSO₃, cold 6% NaHCO₃ (2×125 mL) andbrine. The organic phase was dried with MgSO₄ and concentrated. Flashchromatography (silica gel, 25-35% ethyl acetate/hexane) provided 1.52 g(40%) of title compound as a white solid.

¹ H NMR (CDCl₃, 300 MHz) δ8.08 (d, J=7.0, 2H); 7.59-7.55 (m, 1H); 7.46(t, J=7.2, 2H); 7.38-7.25 (m, 20H); 6.30 (t, J=8.5, 1H); 5.65 (d, J=6.8,1H); 5.49-5.39 (m, 4H); 5.32 (s, 1H); 5.18-4.19 (m, 4H); 4.93 (d, J=9.2,1H); 4.44 (dd, J=6.6, J=10.2, 1H); 4.31 (d, J=8.4, 1H); 4.16 (d, J=8.5,1H); 3.80 (d, J=6.9, 1H); 2.69-2.39, (m, 4H), 2.33-2.23 (m, 3H); 2.03(s, 3H); 1.90 (t, J=12.6, 1H); 1.68-1.63 (m, 6H); 1.28 (s, 9H);1.16-1.10 (m, 6H); 0.93 (t, J=7.4, 9H); 0.55 (q, J=7.8, 6H).

¹³ C NMR (CDCl₃, 75.5 MHz) δ204.1, 169.7, 167.9, 167.1, 151.1, 140.7,135.7, 133.6, 130.2, 129.2, 128.9, 128.8, 128.7, 128.6, 128.5, 128.4,128.3, 128.2, 128.0, 127.8, 126.4, 90.4, 84.2, 81.1, 80.4, 79.3, 78.8,74.9, 72.8, 72.0, 70.5, 69.2, 69.1, 69.0, 58.1, 46.8, 43.2, 37.1, 35.0,28.1, 26.5, 22.8, 21.0, 14.1, 10.0, 6.9, 5.5.

M. S. (FAB) m/z+: 1345

(f) Preparation of10-desacetyl-2'-O-benzyloxycarbonyl-3'-N-debenzoyl-3'-N-(t-butyloxycarbonyl)-10-O-(dibenzylphosphonooxymethyl)paclitaxel##STR76##

A solution of the product of step (e) (50.8 mg, 0.038 mmol) in dry THF(2.5 mL), under argon was cooled to -40° C. To this solution was addedtetrabutylammonium fluoride (0.057 mL, 0.057 mmol) in THF (1.0M) in adropwise manner. The reaction mixture stirred for 1.5 h with gradualwarming to -20° C. The mixture was quenched with 15 mL sat. NH₄ Cl anddiluted with 30 mL EtOAc. The organic phase was washed with 2×15 mLNaHCO₃, and brine. It was dried with MgSO₄ and concentrated. Preparativelayer chromatography (silica gel, 50% ethyl acetate/hexane) provided 36mg (77%) of title compound as a white powder.

¹ H NMR (CDCl₃, 300 MHz) δ8.10 (d, J=8.5, 2H); 7.60-7.55 (m, 1H);7.49-7.44 (m, 2H); 7.36-7.18 (m, 20H); 6.27-6.22 (m, 1H); 5.78 (s, 1H);5.67 (d, J=7.0, 1H); 5.44-5.34 (m, 3H); 5.27 (d, J=2.2, 1H); 5.24-5.05(m, 4H); 5.01-4.91 (m, 4H); 4.39-4.28 (m, 2H); 4.17 (d, J=8.2, 1H); 3.87(d, J=7.0, 1H); 2.58-2.51 (m, 1H); 2.41 (s, 3H); 2.40-2.18 (m, 2H),2.00-1.87 (m, 5H); 1.73-1.69 (m, 4H); 1.30 (s, 9H); 1.22-1.15 (m, 6H).

M.S. (FAB) m/z+: 1231

(g) Preparation of10-desacetyl-3'-N-desbenzoyl-3'-N-(t-butyloxycarbonyl)-10-O-(phosphonooxymethyl)paclitaxeltriethanolamine salt ##STR77##

A 500 mL Parr bottle was charged with10-desacetyl-2'-O-benzyloxycarbonyl-3'-N-debenzoyl-3'-N-(t-butyloxycarbonyl)-10-O-(dibenzylphosphonooxymethyl)paclitaxel(264.9 mg, 0.215 mmol) and ethyl acetate (20 mL). The flask was thenflushed with argon and 10% Pd/C (318 mg) was added. The resultingmixture was placed on a Parr apparatus with a 55 pounds per square inch(psi) hydrogen atmosphere. The reaction was monitored by HPLC (70:30 CH₃CN/Q8 buffer pH 6.0, 1.00 mL/min., Zorbax C-18 column, 25.0 cm, λ=230nm) until no starting material was evident (12.5 hours). The mixture wasfiltered through a plug of Celite, which was washed with ethyl acetateand a small amount of dichloromethane. The resulting filtrate wasconcentrated and the residue was taken up in 5 dichloromethane (5 mL).Addition of hexane caused a white precipitate to form, of which 140.3 mgof the free acid (80% purity by HPLC) was isolated as a white solid.This material was passed directly on to the next step.

To a flask containing the above free acid (140 mg, 0.153 mmol) was addeddichloromethane (10 mL). The resulting solution was then treated with0.100M triethanolamine solution in ethyl acetate (1.16 mL, 0.116 mmol)which caused the solution to become turbid. Approximately 2 mL of hexanewas added and the mixture was placed at -20° C. overnight. The resultingprecipitate was filtered through a 4.0-5.5 μm fritted glass funnel. Thesolid was removed and placed under vacuum for 4 h to yield 69.9 mg (42%)the title triethanolamine salt as a gray powder, which was determined tobe 95-96% pure by HPLC analysis. (T_(R) =2.05 min, 70:30 CH₃ CN/Q8Buffer pH 6.0, 1.00 mL/min, Zorbax C-18 25.0 cm, λ=230 nm).

¹ H-NMR (d₆ -acetone/D₂ O, 300 MHz): δ8.03 (d, J=7.4, 2H); 7.65 (t,J=7.3, 1H); 7.54 (t, J=7.6, 2H); 7.42-7.33 (m, 5H); 7.21 (t, J=7.0, 1H);6.09 (t, J=9.0, 1H); 5.81 (s, 1H); 5.59 (d, J=7.0, 1H); 5.12 (bs, 2H);4.93 (d, J=8.4, 2H), 4.56 (d, J=4.9, 1H); 4.31-4.26 (m, 1H); 4.11 (s,2H); 3.41-3.37 (m, 6H); 2.42-2.32 (m, 5H); 2.15 (bs, 1H); 1.97 (s, 3H);1.77-1.64 (m, 2H); 1.58 (s, 3H); 1.13 (s, 9H); 1.15-1.07 (m, 6H).

¹³ C NMR (d₆ -acetone, D₂ O, 75.6 MHz): δ171.6, 166.9, 156.6, 141.8,135.1, 134.2, 131.0, 130.7,129.4, 129.3, 128.4, 128.1, 88.3, 85.4, 81.9,79.7, 78.6, 78.1, 76.8, 76.0, 74.8, 71.9, 71.2, 47.4, 44.0, 37.1, 36.3,28.5, 27.0, 23.1, 22.0, 14.7, 10.4.

HRMS: MNa⁺, 940.3142 (Calculated for C₄₄ H₅₆ NO₁₈ PNa=940.3133)

Example 10 2'-O-Phosphonooxymethoxymethylpaclitaxel (a) Preparation of2'-O-(methylthiomethoxymethyl)-7-O-triethysilylpaclitaxel ##STR78##

To a solution of 7-O-triethylsilylpaclitaxel (70.0 mg, 72.2 mmol),bis(methylthiomethyl)ether (90 mg, 72.2 mmol), molecular seives (70 mg),and N-iodosuccinimide (160 mg, 72.2 mmol) in THF (2.0 ml) at roomtemperature was added silver triflate (5.0 mg, 19.5 mmol) and theresulting solution was stirred for 2 h. The reaction mixture was thendiluted with ethyl acetate and filtered through a pad of celite. Thefiltrate was washed with saturated aqueous sodium bicarbonate solution,followed by a 1:1 (v:v) mixture of saturated aqueous sodium bicarbonateand 5% aqueous sodium thiosulfate solution and finally brine. Theorganics were then dried over sodium sulfate and concentrated in vacuo.The residual oil was purified via flash chromatography (3:1,hexanes:ethyl acetate) to provide 22.0 mg (29%) of the title compound asa white solid:

¹ H NMR (300 MHz, CDCl₃) δ8.12-7.20 (15H, m), 7.04 (1H, d, J=8.9 Hz),6.41 (1H, s), 6.25 (1H, m), 5.81 (1H, dd, J=8.9, 2.4 Hz), 5.68 (1H, d,J=7.0 Hz), 4.93 (1H, d, 8.0 Hz), 4.79 (2H, m), 4.71 (1H, d, 2.4 Hz),4.45 (1H, dd, J=10.5, 6.6 Hz), 4.30 (1H, d, J=8.3 Hz), 4.28 (1H, d,J=11.7 Hz), 4.17 (1H, d, J=8.3 Hz), 4.04 (1H, d, J=11.7 Hz), 3.80 (1H,d, J=6.9 Hz), 2.48-1.13 (25H, m, incl. singlets at 2.51, 2.13, 2.05,2.01, 1.69, 1.19, 1.16), 0.98-0.85 (9H, m), 0.65-0.50 (6H, m).

(b) Preparation of2'-O-(dibenzylphosphonooxymethoxymethyl)-7-triethylsilylpaclitaxel##STR79##

To a solution of the product obtained in step (a) (15 mg, 0.0141 mmol)and molecular sieves (15 mg) in THF (0.5 ml) at room temperature wasadded dibenzyl phosphate (20.0 mg, 0.089 mmol) followed byN-iodosuccinimide (4.2 mg, 0.0187 mmol) and the solution was stirred for1 h. A TLC analysis of the reaction mixture at this time indicated thepresence of starting material only. Silver triflate (5.0 mg, 0.019 mmol)was then added in three portions over 2 h and the reaction was stirredfor an additional 1 h. The reaction mixture was then diluted with ethylacetate and the resulting solution filtered through a pad of celite. Thefiltrate was treated with a 1:1 (v:v) solution of saturated aqueoussodium bicarbonate and 5% aqueous sodium thiosulfate solution. Theorganic extract was then washed with brine, dried over sodium sulfateand concentrated in vacuo. The residual oil was purified via flashchromatography (1:1, hexanes:ethyl acetate) to provide 5.0 mg (33%) ofthe title compound:

¹ H NMR (300 MHz, CDCl₃) δ8.08-7.16 (25H, m), 7.18 (1H, d, J=8.8 Hz),6.41 (1H, s), 6.21(1H, m), 5.82 (1H, dd, J=9.0, 3.1 Hz), 5.66 (1H, d,7.0 Hz), 5.01-4.65 (10H, m), 4.56 (1H, dd, J=14.7, 5.6 Hz), 4.43(1H, dd,J=10.4, 6.7 Hz), 4.29 (1H, d, J=8.3 Hz), 4.16 (1H, d, J=8.3 Hz), 3.78(1H, d, J=7.0 Hz), 2.60-1.13 (22H, m, incl. singlets at 2.49, 2.15,1.93, 1.66, 1.15, 1.13, 3H each), 0.95-0.84 (9H, m), 0.63-0.45 (6H,m).

(c) Preparation of 2'-O-phosphonooxymethoxymethylpaclitaxel ##STR80##

The product of step (b) is treated with tetrabutylammonium fluorideaccording to the procedure given in Example 9(f) to remove the7-O-triethylsilyl protecting group. The compound thus obtained issubject to catalytic hydrogenation according to the procedure describedin previous examples to provide the title compound.

Example 11 2'-O-Phosphonooxymethoxymethylpaclitaxel (Alternate route)(a) Preparation of 2'-O-triethylsilylpaclitaxel ##STR81##

To a solution of paclitaxel (20.0 g, 0.0234 mol) and imidazole (3.59 g,0.052 mol) in 150 mL of DMF (dimethylformamide) at 0° C. was addedtriethylsilyl chloride (6.0 mL, 0.053 mol) in 2.0 mL quantities over 20min. The reaction mixture was then stirred at 0° C. for 1 h. The mixturewas then diluted with ethyl acetate and saturated aqueous ammoniumchloride. The organic layer was removed, washed with brine, dried oversodium sulfate and concentrated in vacuo to provide a yellow oil.Purification of the crude product via flash chromatography(hexanes:ethyl acetate: 1:3 then 1:1) provided 21.07 g (98% yield) ofthe desired title compound as a colorless white solid.

¹ H-NMR (300 MHz, CDCl₃) δ8.15 (2H, m), 7.70 (2H, m), 7.65-7.30 (11H, m)7.15 (1H, d, J=8.9 Hz), 6.30 (1H, s), 6.25 (1H, m), 6.70-6.10 (2H, m),4.94 (1H, d, J=7.9 Hz), 4.67 (1_(H), d, 2.0 Hz), 4.40 (1H, m), 4.29 (1H,d, J=8.4 Hz), 4.18 (1H, d, J=8.4 Hz), 3.81 (1H, d, J=7.1 Hz), 2.65-1.10(22H, including singlets at 2.55, 2.20, 1.88, 1.69, 1.22, 1.13, 3Heach).

(b) Preparation of 2'-O-triethylsilyl-7-O-benzyloxycarbonylpaclitaxel##STR82##

Butyllithium (1.6M in hexanes, 12.9 mL, 8.06 mmol) was added dropwiseover 10 min to a solution of 2'-O-triethylsilylpaclitaxel (22.3 g, 24.1mmol) in THF (250 mL) cooled to -50° C. The resulting solution wasstirred for 20 min and the temperature maintained between -50° C. and-35° C. The reaction mixture was then cooled to -50° C. and benzylchloroformate (5.08 mL, 29.8 mmol) was added dropwise over 5 min. Thereaction mixture was maintained at -40° C. for 30 min then equilibratedto 0° C. over approximately 30 min. The mixture was then diluted withethyl acetate and saturated aqueous ammonium chloride and the resultingorganic layer washed with brine, dried over sodium sulfate andconcentrated in vacuo. A ¹ H-NMR analysis of the crude reaction mixtureshowed the presence of desired2'-O-triethylsilyl-7-O-benzyloxycarbonylpaclitaxel as well as2'-O-triethylsilyl-7-epihydroxypaclitaxel (3:1 ratio, respectively).This product mixture was used in the next step without furtherpurification and the isomers subsequently separated. An analyticalsample of the major product2'-O-triethylsilyl-7-O-benzyloxycarbonylpaclitaxel was purified viaflash chromatography; ¹ H-NMR (300 MHz, CDCl₃) δ8.12 (2H, m), 7.72 (1H,m), 7.65-7.27 (1H, d, J=8.8 Hz), 6.41 (1H, m), 6.20 (1H, m), 5.72-5.65(2H, m), 5.52 (1H, m), 5.24 (1H, d, J=12.3 Hz), 5.16 (1H, d, J=12.3 Hz),4.95 (1H, d, J=8.7 Hz), 4.69 (1H, s), 4.35 (1H, d, J=8.3 Hz), 4.25 (1H,d, J=8.3 Hz), 3.94 (1H, d, J=6.8 Hz), 2.70-1.12 (22H, including singletsat 2.54, 2.14, 2.01, 1.80, 1.20, 1.15, 3H each), 0.81-0.73 (9H, m),0.55-0.31 (6H, m).

(c) Preparation of 7-O-benzyloxycarbonylpaclitaxel ##STR83##

Hydrochloric acid (6N, 1.0 mL, 6.0 mmol) was added to a solution theproduct from Step (b) (24.0 g, 22.6 mmol) in acetonitrile (250 mL)cooled to 0° C. After 10 min a TLC analysis (hexanes:ethyl acetate, 1:1)indicated the reaction was complete. The reaction mixture was dilutedwith saturated aqueous sodium bicarbonate followed by ethyl acetate andthe organic layer was removed, washed with brine, dried using sodiumsulfate and concentrated in vacuo. The residual oil was purified usingflash chromatography (hexanes:ethyl acetate, 1:3, then 1:1) to provide11.4 g (48% over 2 steps) of the title compound and 4.8 g (20%) of7-epihydroxypaclitaxel.

¹ H-NMR (300 MHz, CDCl₃) δ8.09 (2H, m), 7.71 (2H, m), 7.65-7.27 (16H,m), 7.10 (1H, d, 8.9 Hz), 6.39 (1H, s), 6.16 (1H, m), 5.81 (1H, d,J=8.9, 2.4 Hz), 5.65 (1 H, d, J=6.9 Hz), 5.49 (1H, dd, J=10.6, 7.2 Hz),5.20 (1H, d, J=11.9 Hz), 5.12 (1H, d, J=11.9), 4.91 (1H, d, J=8.4 Hz),4.78 (1H, m), 4.30 (1H, d, J=8.4 Hz), 4.15 (1H, d, J=8.4 Hz), 3.91 (1H,d, J=6.8 Hz), 3.69 (1H, d, J=4.9 Hz), 2.65-1.10 (22H, including singletsat 2.39, 2.18, 1.81, 1.75, 1.21, 1.15, 3H each).

(d) Preparation of2'-O-(methylthiomethoxymethyl)-7-O-benzyloxycarbonylpaclitaxel ##STR84##

Silver triflate (300 mg, 1.17 mmol) was added to a solution7-O-benzyloxycarbonylpaclitaxel (5.53 g, 5.71 mmol), 1,1'-dithiomethyldimethyl ether (7.8 g, 57.1 mmol), N-iodosuccinimide(6.35 g, 28.3 mmol) and oven dried, powdered molecular sieves (5.0 g) inTHF (110 mL) at room temperature. A TLC analysis (hexanes:ethyl acetate,1:1) of the reaction mixture after 20 min indicated the conversion ofapproxiately 40% of the starting material to a higher running product.Silver triflate (150 mg, 0.585 mmol) was then added and the reaction wasmonitored by TLC which indicated after 30 min the reaction wasappoximately 65% complete. The mixture was diluted with ethyl acetate(100 mL), filtered using a pad of celite and the filtrate was pouredinto a separatory funnel containing 200 mL of a saturated aqueoussolution of sodium bicarbonate and 50 mL of a 5% aqueous sodiumthiosulfate solution. The organic layer was removed, washed with brine,dried over sodium sulfate and concentrated in vacuo. The residual oilwas purified via flash chromatography (hexanes:ethyl acetate, gradientelution 4:1 to 3:2) to provide 3.0 g (54% yield) of the title product asa light yellow solid.

¹ H-NMR (300 MHz, CDCL₃) δ8.10 (2H, m), 7.74 (2H, m), 7.66-7.25 (18H,m), 7.05 (1H, d, J=8.9 Hz), 6.40 (1H, s), 6.26 (1H, m), 5.77 (1H, dd,J=8.8, 2.5 Hz), 5.71 (1H, d, J=6.9 Hz), 5.51 (1H, dd, J=10.6, 7.1 Hz),5.21 (1H, d, J=11.9 Hz), 5.14 (1 H, d, J=11.9 Hz), 4.92 (1H, m), 4.79(2H, m), 4.68 (1H, d, J=2.5 Hz), 4.31 (1H, d, J=11.8 Hz), 4.30 (1H, d,J=8.5 Hz), 4.16 (1H, d, J=8.5 Hz), 4.10 (1H, d, J=11.8 Hz), 3.93 (1H, d,J=6.9 Hz), 2.65-1.10 (25H including singlets at 2.50, 2.15, 2.05, 1.74,1.72, 1.20, 1.15, 3H each).

(e) Preparation of2'-O-(dibenzylphosphonooxymethoxymethyl)-7-O-benzyloxycarbonylpaclitaxel##STR85##

To a solution of2'-O-(methylthiomethoxymethyl)-7-O-benzyloxycarbonylpaclitaxel (1.06 g,1.07 mmol) and oven dried, powdered molecular sieves (1.0 g) in THF (20mL) at room temperature was added dibenzyl phosphate (1.49 g, 5.30 mmol)followed immediately by N-iodosuccinimide (2.65 g, 1.18 mmol). A TLCanalysis (hexanes:ethyl acetate 1:1) of the reaction mixture after 2.5 hindicated the reaction was approximately 60% complete. N-iodosuccinimide(175 mg, 0.78 mmol) was then added and the reaction stirred for anadditional 30 min, after which time a TLC analysis indicated thereaction was complete. The reaction mixture was then diluted with ethylacetate (50 mL) and filtered using a pad of celite. The filtrate waspoured into a separatory funnel containing 100 mL of a saturated aqueoussolution of sodium bicarbonate and 20 mL of a 5% aqueous solution ofsodium thiosulfate. The organic layer was removed, washed with brine,dried over sodium sulfate and concentrated in vacuo. The residual oilwas purified using flash chromatography (hexanes:ethyl acetate, gradientelution, 3:1 to 1:1) to provide 750 mg (62% yield) of the desired titlecompound as a white solid.

¹ H-NMR (360 MHz, CDCl₃) δ8.10 (2H, m), 7.79 (2H, m), 7.65-7.24 (26H,m), 7.10 (1H,m), 6.41 (1H, s), 6.20 (1H,m), 5.79 (1H, dd, J=8.8, 3.6Hz), 5.65 (1H, d, J=7.0 Hz), 5.52 (1H,m), 5.20 (1H, d, J=11.8 Hz), 5.11(1H, d, J=11.8 Hz), 5.04-4.85 (6H, m), 4.75-4.60 (4H, m), 4.30 (1H, d,8.4 Hz), 4.15 (1H, d,J=8.4 Hz), 3.92 (1H, d, J=7.0 Hz) 2.65-1.10 (22Hincluding singlets at 2.48, 2.19, 1.95, 1.80, 1.20, 1.10, 3H each).

(f) Preparation of 2'-O-phosphonooxymethoxymethylpaclitaxeltriethanolamine salt

Palladium (10%) on carbon was added to a solution of2'-O-(dibenzylphosphonooxymethoxymethyl)-7-O-benzyloxycarbonylpaclitaxel(500 mg, 0.382 mmol) in ethly acetate (40 mL) housed in a Parr bottle.The vessel was affixed to a Parr apparatus and the reaction mixturesubjected to hydrogen at 50 psi. The reaction mixture was shaken for 6.5h, then filtered using a sintered glass funnel. Triethanolamine (0.1N inethyl acetate, 4.0 mL) was added to this filtrate and the resultingsolution was concentrated in vacuo. The crude solid was suspended inapproximately 5.0 mL of ethyl acetate and the solvent decanted. Thisprocess was repeated three times and the resulting title triethanolaminesalt (300 mg) was obtained with purity of 87% as determined by HPLCanalysis. Further purification of this compound via C18 chromatography(water:acetonitrile, 3:1) provided the desired title compound (120 mg,34%) at 95% purity by HPLC.

¹ H-NMR (300 MHz, CD₃ COCD₃, D₂ O) δ9.05 (1H, d, J=8.7 Hz), 8.15-7.12(21H, m), 6.40 (1H,m), 6.05 (1H, m), 5.69-5.55 (2H, m), 5.01-4.85 (6H,m), 4.35 (1H, m), 4.14 (2H, m), 3.96-3.85 (6H, m), 3.25 (1H, d, J=7.1Hz), 3.30-3.15 (6H, m) 2.50-1.04 (22H, including singlets at 2.49, 2.15,2.05, 1.81, 1.60, 3H each).

Example 123'-N-debenzoyl-3'-N-(isopropyloxycarbonyl)-7-O-methylthiomethylpaclitaxel##STR86##

To a solution of 7-O-methylthiomethylbaccatin III (408 mg, 0.630 mmol)in 10 mL of THF at -60° C. was added nBuLi (0.30 mL, 2.5M, 0.75 mmol)and stirred for 10 min. (3R,4S)-3-Triethylsilyloxy-4-phenyl-N-isopropyloxycarbonylazetidin-2-one(320 mg, 0.88 mmol) in 6 mL of THF was added dropwise and then thereaction brought to 0° C. for 30 min. The solution was quenched withsaturated NH₄ Cl and extracted with ethyl acetate, shaken with Bu₄ NF(1.0 mL, 1.0M, 1.0 mmol) and then washed with brine, dried over MgSO₄and concentrated. The residue was chromatographed over silica gel (1.5:1hexane/ethyl acetate) to give 545 mg of a product which was crystalizedfrom acetone/hexane to give 476 mg of the title product as a white solid(84%); IR(KBr) 3460, 1720, 1266, 1244, 1230 cm⁻¹ ; ¹ H-NMR (CDCl₃, 300MHz) δ8.07 (d, J=7.2 Hz, 2H), 7.59 (t, J=7.2 Hz, 1H), 7.47 (t, J=7.5 Hz,2H), 7.32 (m, 5H), 6.51 (s, 1H), 6.18 (t, J=8.7 Hz, 1H), 5.65 (d, J=6.6Hz, 1H), 5.50 (d, J=9.3 Hz, 1H), 5.28 (d J=8.4 Hz, 1H), 4.91 (d, J=8.1Hz, 1H), 4.77 (m, 1H), 4.64 (bs, 3H), 4.26 (m, 2H), 4.15 (d, J=8.4 Hz,1H), 3.83 (d, J=6.9 Hz, 1H), 3.44 (d, J=5.1 Hz, 1H), 2.78 (m, 1H), 2.34(s, 3H), 2.25 (d, J=9.0 Hz, 2H), 2.17 (s, 3H), 2.14 (s, 1H), 2.10 (s,3H), 1.96 (s, 3H), 1.83 (m, 1H), 1.73 (s, 3H), 1.15 (m, 12H); ¹³ C NMR(CDCl₃, 75.5 Hz) δ201.8, 170.4, 169.2, 167.0, 156.3, 140.1, 138.3,133.7, 133.3, 130.2, 129.1, 128.8, 128.6, 128.1, 126.8, 83.8, 81.4,78.7, 76.0, 75.5, 74.5, 74.0, 73.6, 72.2, 68.9, 57.5, 56.4, 47.1, 43.2,35.3, 32.9, 26.6, 22.6, 22.0, 21.9, 20.9, 15.1, 14.6, 10.9

FABMS (NOBA) M+Na calcd for C₄₆ H₅₇ NSO₁₅ : 918. Found: 918.

Anal. calcd for C₄₆ H₅₇ NSO₁₅ : C, 61.66; H, 6.41; N, 1.56. Found: C,61.63; H, 6.36; N, 1.68.

Example 133'-N-Debenzoyl-3'-N-(n-butyloxycarbonyl)-7-O-methylthiomethylpaclitaxel##STR87##

To a solution of 7-O-methylthiomethylbaccatin III (425 mg, 0.66 mmol) in10 mL of THF at -60° C. was added nBuLi (0.30 mL, 2.5M, 0.75 mmol) andstirred for 10 min.(3R,4S)-3-Triethylsilyloxy-4-phenyl-N-(n-butyloxycarbonyl)azetidin-2-one(350 mg, 0.93 mmol) in 6 mL of THF was added dropwise and then thereaction brought to 0° C. for 30 min. The solution was quenched withsaturated NH₄ Cl and extracted with ethyl acetate, shaken with Bu₄ NF(1.0 mL, 1.0M, 1.0 mmol) and then washed with brine, dried over MgSO₄and concentrated. The residue was chromatographed over silica gel (1.5:1hexane/ethyl acetate) to give 581 mg of the title product which wascrystalized from toluene/hexane to give 464 mg of a white solid (77%);IR(KBr) 3444, 1722, 1372, 1242, 1108, 1066, 1026, 988 cm⁻¹ ; ¹ H-NMR(CDCl₃, 300 MHz) δ8.08 (d, J=7.2 Hz, 2H), 7.59 (t, J=7.5 Hz, 1H), 7.47(t, J=7.2 Hz, 2H), 7.39-7.11 (m, 5H), 6.51 (s, 1H), 6.20 (t, J=8.7 Hz,1H), 5.65 (d, J=6.9 Hz, 1H), 5.56 (d, J=9.3 Hz, 1H), 5.29 (d J=8.4 Hz,1H), 4.91 (d, J=8.1 Hz, 1H), 4.65 (bs, 3H), 4.27 (m, 2H), 4.15 (d, J=8.4Hz, 1H), 3.97 (m, 2H), 3.84 (d, J=6.9 Hz, 1H), 3.45 (d, J=4.8 Hz, 1H),2.78 (m, 1H), 2.33 (s, 6H), 2.25 (d, J=8.7 Hz, 2H), 2.17 (s, 3H), 2.10(s, 3H), 1.96 (s, 3H), 1.83 (m, 1H), 1.74 (s, 3H), 1.62 (s, 1H), 1.48(m, 2H), 1.19 (m, 5H), 0.83 (t, J=7.2 Hz, 3H); ¹³ C NMR (CDCl₃, 75.5 Hz)δ 201.9, 172.3, 170.5, 169.2, 167.0, 156.3, 140.1, 138.4, 133.8, 133.4,130.2, 129.2, 129.0, 128.9, 128.7, 128.2, 126.8, 125.3, 83.9, 81.4,78.8, 77.3, 76.0, 75.6, 74.6, 74.1, 73.7, 72.2, 65.4, 57.5, 56.5, 47.2,43.2, 35.4, 26.6, 22.6, 21.5, 21.0, 18.9, 15.1, 14.7, 13.7, 10.9.

FABMS (NOBA) M+H calcd for C₄₇ H₆₀ NSO₁₅ : 910. Found: 910.

Anal. calcd for C₄₇ H₅₉ NSO₁₅ : C, 62.03; H, 6.53; N, 1.54. Found: C,62.16; H, 6.45; N, 1.57.

Example 143'-N-debenzoyl-3'-N-(t-butoxycarbonyl)-7-O-methythiomethylpaclitaxel (a)Preparation of3'-N-debenzoyl-3'-N-(t-butoxycarbonyl)-2-O-triethylsilyl-7-O-methylthiomethylpaclitaxel##STR88##

To a solution of HMDS (0.275 mL, 1.30 mmol) in 8 mL of THF was added asolution of n-BuLi (0.48 mL, 2.5 M in hexanes, 1.20 mmol) and stirred 5minutes at -55° C. To this solution was added methylthiomethylbaccatinIII (639 mg, 0.99 mmol) in 8 mL of THF and stirred for 10 minutes beforeaddition of an 8 mL solution of(3R,4S)-3-triethylsilyloxy-4-phenyl-N-(t-butoxycarbonyl)azetidin-2-one(575 mg, 1.52 mmol). The cold bath was removed and replaced with a 0° C.bath and the reaction stirred for 30 minutes. The solution was dilutedwith ethyl acetate and washed with saturated NH₄ Cl solution, dried overMgSO₄ and concentrated. The residue was chromatographed over silica gel(3:1 hexane/ethyl acetate) to give 1.0 g of the title product (98%); ¹H-NMR (CDCl₃, 300 MHz) δ8.09 (d, J=6.9 Hz, 2H), 7.57 (m, 1H), 7.46 (t,J=7.8 Hz, 2H), 7.35 (m, 2H), 7.26 (m, 3H), 6.55 (s, 1H), 6.25 (t, J=9.6Hz, 1H), 5.68 (d, J=6.9 Hz, 1H), 5.45 (bd, J=9.3 Hz, 1H), 5.27 (bd, 1H),4.95 (d, J=7.8 Hz, 1H), 4.65 (s, 2H), 4.53 (s, 1H), 4.29 (m, 2H), 4.17(d, J=8.4 Hz, 1H), 3.89 (d, J=6.9 Hz, 1H), 2.81 (m, 1H), 2.51 (s, 3H),2.37 (dd, J=15.3, 9.6 Hz, 1H), 2.17 (S, 3H), 2.10 (S, 3H), 2.03 (s, 3H),1.85 (m, 1H), 1.74 (s, 3H), 1.63 (d, J=14.1 Hz, 1H), 1.29 (s, 9H), 1.21(s, 6H), 0.76 (t, J=7.8 Hz, 9H), 0.36 (m, 6H); ¹³ C-NMR (CDCl₃, 75.5 Hz)δ202.0, 171.6, 170.1, 169.3, 167.1, 155.2, 141.0, 139.0, 133.6, 132.8,130.2, 129.2, 128.7, 128.5, 127.7, 126.4, 83.9, 81.2, 79.9, 78.9, 76.0,75.7, 75.2, 74.8, 74.2, 71.3, 57.3, 56.7, 47.0, 43.3, 35.3, 33.0, 28.2,26.4, 23.0, 21.5, 21.0, 15.0, 14.4, 10.9, 6.5, 4.3; IR(film) 3448 (s),1720, 1242, 1120, 1056 cm⁻¹.

FABMS (NOBA) M+H calcd for C₅₃ H₇₄ NSSiO₁₅ : 1024.4549. Found:1024.4583.

(b) Preparation of3'-N-debenzoyl-3'-N-(t-butoxycarbonyl)-7-O-methylthiomethylpaclitaxel##STR89##

To a solution of the3'-N-debenzoyl-3'-N-(t-butoxycarbonyl)-2-O-triethylsilyl-7-O-methylthiomethylpaclitaxel(269 mg, 0.26 mmol) in 6 mL of THF was added tetrabutylammonium fluoride(0.3 mL, 1.0M in THF, 0.3 mmol) and stirred 10 minutes. The solution wasdiluted with ethyl acetate and washed with brine, dried over MgSO₄ andconcentrated and the residue was chromatographed over silica gel (1:1hexane/ethyl acetate) to give 240 mg of the title product (95%);IR(film) 3440, 1720, 1370, 1242, 1170, 1108, 1066, 756 cm⁻¹ ; ¹ H-NMR(CDCl₃, 300 MHz) δ8.06 (d, J=7.2 Hz, 2H), 7.57 (t, J=7.2 Hz, 1H), 7.46(t, J=7.8 Hz, 2H), 7.35 (m, 5H), 6.52 (s, 1H), 6.16 (t, J=8.7 Hz,1H),5.64 (d, J=6.9 Hz, 1H), 5.43 (bd, J=9.3 Hz, 1H), 5.24 (bd, J=8.1 Hz,1H), 4.91 (d, J=8.1 Hz, 1H), 4.63 (m, 3H), 4.26 (m, 2H), 4.14 (d, J=8.4Hz, 1H), 3.83 (d, J=6.9 Hz, 1H), 3.46 (d, J=5.4 Hz, 1H), 2.77 (m, 1H),2.34 (s, 3H), 2.27 (d, J=8.7 Hz, 2H), 2.16 (s, 3H), 2.09 (s, 3H), 1.97(s, 3H), 1.79 (m, 2H), 1.72 (s, 3H), 1.32 (s, 9H), 1.19 (s, 3H), 1.18(s, 3H); ¹³ C-NMR (CDCl₃, 75.5 Hz) δ202.0, 172.7, 170.3, 169.2, 167.0,155.3, 140.3, 138.4, 133.7, 133.2, 130.2, 129.1, 128.8, 128.7, 128.0,126.7, 83.9, 81.3, 80.2, 78.6, 76.5, 76.1, 75.4, 74.6, 74.0, 73.6, 72.3,57.4, 56.1, 47.1, 43.2, 35.3, 32.8, 28.2, 26.5, 22.6, 21.0, 15.1, 14.6,10.9.

FABMS (NOBA) M+H calcd for C₄₇ H₆₀ NO₁₅ S: 910.3684. Found: 910.3706.

Example 153,-N-debenzoyl-3'-N-(t-butoxycarbonyl)-2'-O-ethyloxycarbonyl-7-O-methylthiomethylpaclitaxel##STR90##

To a solution of3'-N-debenzoyl-3'-N-(t-butoxycarbonyl)-7-O-methylthiomethylpaclitaxel(428 mg, 0.47 mmol) in 10 mL of dichloromethane was addeddiisopropylethyl amine (0.85 mL, 4.8 mmol) and DMAP (20 mg) and cooledto 0° C. The ethyl chloroformate (0.25 mL, 2.6 mmol) was then added andstirred for 1 hr. The solution was diluted with ethyl acetate and washedwith bicarbonate and brine, dried (MgSO₄) and concentrated. The residueso obtained was chromatographed over silica gel (1:1 hexane/ethylacetate) to give 428 mg of the title ethyl carbonate (92%); IR(film)3448 (w), 1750, 1720, 1370, 1244, 1064 cm⁻¹ ; ¹ H-NMR (CDCl₃, 300 MHz)δ8.09 (d, J=7.2 Hz, 2H), 7.59 (t, J=7.2 Hz, 1H), 7.48 (t, J=7.8 Hz, 2H),7.39 (m, 2H), 7.31 (m, 3H), 6.55 (s, 1H), 6.25 (t, J=9.0 Hz, 1H), 5.68(d, J=7.2 Hz, 1H), 5.40 (bm, 2H), 5.25 (s, 1H), 4.95 (d, J=8.1 Hz, 1H),4.65 (S, 2H), 4.29 (m, 2H), 4.15 (m, 3H), 3.88 (d, J=6.9 Hz, 1H), 2.81(m, 1H), 2.43 (s, 3H), 2.32 (m, 1H), 2.21 (m, 1H), 2.16 (s, 3H), 2.11(s, 3H), 2.08 (s, 3H), 1.84 (m, 1H), 1.74 (s, 3H), 1.62 (s, 1H), 1.32(s, 9H), 1.28 (t, J=7.2 Hz, 3H), 1.20 (s, 6H); ¹³ C-NMR (CDCl₃, 75.5 Hz)δ202.0, 169.7, 169.1, 168.1, 167.0, 155.1, 154.1, 141.0, 137.2, 133.6,132.9. 130.2., 129.2, 128.9, 128.7, 128.2, 126.4, 83.9, 81.2, 80.4,78.9, 76.5, 76.0, 75.8, 74.8, 74.2, 72.0, 65.1, 57.4, 47.1, 43.3, 35.1,33.0, 28.1, 26.4, 22.7, 21.3, 20.9. 15.0, 14.5, 14.1, 10.9.

FABMS (NOBA) M+H calcd for C₅₀ H₆₄ NSO₁₇ : 982.3895. Found: 982.3874.

Example 163'-N-Debenzoyl-3'-N-(t-butoxycarbonyl)-7-O-methylthiomethyl-10-deacetyl-10-hydroxymethylcarbonyl(paclitaxel)(a) Preparation of7-O-Triethylsilyl-10-deacetyl-10-benzyloxymethylcarbonyl baccatin III##STR91##

To a solution of 7-O-triethylsilyl-10-deacetylbaccatin III (3.85 g, 5.85mmol) in 40 mL of THF at -60° C. was added n-BuLi (2.6 mL, 2.5M inhexanes, 6.5 mmol) and stirred for 5 min before addition ofbenzyloxyacetyl chloride (1.0 mL, 6.5 mmol). After stirring for 30 minat -60° C. and then warming to ambient temperature the solution wasdiluted with ethyl acetate and washed with bicarbonate. The solution wasdried over MgSO₄ and concentrated and the residue chromatographed oversilica gel (2:1 then 1:1 hexane/ethyl acetate) to give 4.36 g of product(92%); IR(film) 3478 (br), 1724, 1270, 1244, 1136, 1110, 1070 cm⁻¹ ; ¹H-NMR (CDCl₃, 300 MHz) δ8.08 (d, J=7.2 Hz, 2H), 7.60-7.23 (m, 8H), 6.54(s, 1H), 5.60 (d, J=6.9 Hz, 1H), 4.94 (d, J=7.8 Hz, 1H), 4.79 (bq, 1H),4.69 (s, 2H), 4.49 (dd, J=10.5, 6.6 Hz, 1H), 4.26 (m, 2H), 4.12 (m, 1H),3.85 (d, J=6.9 Hz, 1H), 2.52 (m, 1H), 2.26 (s, 3H), 2.23 (m, 2H), 2.18(s, 3H), 2.10 (m, 1H), 1.86 (m, 1H), 1.66 (s, 3H), 1.14 (s, 3H), 0.99(s, 3H), 0.91 (t, J=7.5 Hz, 9H), 0.56 (m, 6H).

Anal. Calcd. for C₄₄ H₅₈ SiO₁₂ : C, 65.49; H, 7.24. Found: C, 65.33; H,7.27.

FABMS (NOBA) M+H calcd for C₄₄ H₅ SiO₁₂ 807. Found: 807.

(b)3'-N-debenzoyl-3'-N-(t-butoxycarbonyl)-10-deacetyl-10-benzyloxymethylcarbonyl(paclitaxel)##STR92##

To a solution of7-O-triethylsilyl-10-deacetyl-10-benzyloxymethylcarbonyl baccatin III(1.21 g, 1.66 mmol) in 50 mL of THF at -60° C. was added n-BuLi (0.7 mL,2.5M in hexanes, 1.75 mmol) and stirred for 5 min before addition of(3R,4S)-3-triethylsilyloxy-4-phenyl-N-(t-butoxycarbonyl)azetidin-2-one(1.2 g, 3.2 mmol). After stirring for 5 min at -60° C. and then 30 minat 0° C. the solution was diluted with ethyl acetate and washed withsaturated NH₄ Cl. The solution was dried over MgSO₄ and concentrated andthe residue chromatographed over silica gel (3:1 then 1:1 hexane/ethylacetate) to give 980 mg of product (53%). This product was dissolved in6 mL of acetonitrile and cooled to 0° C. and stirred with 0.60 mL of 6NHCl for 19 hrs. The solution was diluted with ethyl acetate and washedwith saturated bicarbonate, dried over MgSO₄ and chromatographed oversilica gel (1:1 hexane/ethyl acetate) to give 570 mg of product (35%);IR(film) 3448 (br), 1716, 1496, 1368, 1316, 1270, 1246, 1176, 1108,1070, 1026 cm⁻¹ ; ¹ H-NMR (CDCl₃, 300 MHz) δ8.08 (d, J=7.5 Hz, 2H), 7.59(t, J=7.8 Hz, 1H), 7.47 (t, J=7.8 Hz, 2H), 7.36 (m, 10H), 6.38 (s, 1H),6.20 (t, J=9.0 Hz, 1H), 5.65 (d, J=6.9 Hz, 1H), 5.39 (bd, J=9.3 Hz, 1H),4.93 (d, J=7.8 Hz, 1H), 4.69 (s, 2H), 4.60 (bs, 1H), 4.39 (m, 1H), 4.28(m, 3H), 4.15 (d, J=8.4 Hz, 1H), 3.78 (d, J=6.9 Hz, 1H), 3.40 (bs, 1H),2.54 (m, 1H), 2.43 (m, 1H), 2.36 (s, 3H), 2.28 (m, 2H), 1.84 (s, 4H),1.72 (m, 1H), 1.67 (s, 3H), 1.31 (s, 9H), 1.23 (m, 1H), 1.21 (s, 3H),1.10 (s, 3H).

Anal. Calcd. for C₅₂ H₆₁ NO₁₆ : C, 65.33; H, 6.43; N, 1.46. Found: C,64.97; H, 6.44; N, 1.43.

FABMS (NOBA) M+Na calcd for C₅₂ H₆₁ NO₁₆ Na 978. Found: 978.

(c) Preparation of3'-N-debenzoyl-3'-N-(t-butoxycarbonyl)-2-O-benzyloxycarbonyl-7-O-methylthiomethyl-10-deacetyl-10-benzyloxymethylcarbonyl(paclitaxel)##STR93##

To a solution of3'-N-debenzoyl-3'-N-(t-butoxycarbonyl)-10-deacetyl-10-benzyloxymethylcarbonyl(paclitaxel)(570 mg, 0.59 mmol) in 10 mL of CH₂ Cl₂ at 0° C. was addeddiisopropylethyl amine (0.15 mL, 0.86 mmol) and CbzCl (0.10 mL, 0.70mmol). The solution was stirred for 1 hr slowly warming to ambienttemperature. The solution was washed with bicarbonate and dried overMgSO₄ and concentrated. The residue in 10 mL of acetonitrile at 0° C.was stirred with benzoyl peroxide (780 mg, 3.22 mmol) anddimethylsulfide (0.50 mL, 6.8 mmol) slowly warming to ambienttemperature over 75 min. The solution was diluted with ethyl acetate andwashed with saturated bicarbonate, dried over MgSO₄ and chromatographedover silica gel (2:1 hexane/ethyl acetate) to give 412 mg of the titleproduct (65%);

IR(film) 3438, 1754, 1722, 1368, 1272, 1244, 1176, 1110, 1066, 1028 cm⁻¹; ¹ H-NMR (CDCl₃, 300 MHz) δ8.11 (d, J=7.2 Hz, 2H), 7.61 (t, J=7.2 Hz,1H), 7.49 (t, J=7.8 Hz, 2H), 7.35 (m, 15H), 6.67 (s, 1H), 6.26 (t, J=8.7Hz, 1H), 5.69 (d, J=6.6 Hz, 1H), 5.41 (bm, 2H), 5.29 (s, 1H), 5.14 (ABq,J=12, 5.7 Hz, 2H), 4.98 (d, J=8 Hz, 1H), 4.72 (m, 4H), 4.32 (m, 3H),4.19 (m, 2H), 3.90 (d, J=6.0 Hz, 1H), 2.85 (m, 1H), , 2.45 (m, 1H), 2.44(s, 3H), 2.34 (m, 1H), 2.24 (m, 1H), 2.15 (s, 3H), 2.12 (s, 3H), 1.87(m, 1H), 1.77 (s, 3H), 1.33 (s, 9H), 1.19 (s, 6H); ⁻⁻ C NMR (CDCl₃, 75.5MHz) δ 201.6, 169.7, 168.7, 168.0, 167.0, 155.1, 154.1, 141.6, 137.1,134.4, 133.7, 132.5, 130.2, 129.2, 128.9, 128.8, 128.7, 128.5, 128.4,128.2, 128.0, 128.0, 126.4, 83.9, 81.2, 80.4, 78.8, 77.2, 76.2, 75.8,74.7, 74.3, 73.4, 72.0, 70.6, 67.1, 57.4, 54.1, 47.1, 43.2, 35.2, 32.9,28.1, 26.4, 22.7, 21.3, 15.2, 14.6, 10.9.

FABMS (NOBA) M+Na calcd for C₆₂ H₇₁ NO₁₈ SNa 1172. Found: 1172.

(d) Preparation of3'-N-debenzoyl-3'-N-(t-butoxycarbonyl)-7-O-methylthiomethyl-10-deacetyl-10-hydroxymethylcarbonyl(paclitaxel)##STR94##

To a solution of3'-N-debenzoyl-3'-N-(t-butoxycarbonyl)-2-O-benzyloxymethylcarbonyl-7-O-methylthiomethyl-10-deacetyl-10-benzyloxycarbonyl(paclitaxel)(377 mg, 0.35 mmol) in 30 mL of ethanol was added a total of 450 mg of10% palladium on carbon catalyst and stirred under an atmosphere ofhydrogen for 120 hrs. The catalyst was removed by filtration throughcelite and the solution concentrated. The residue was chromatographedover silica gel (20% CH₃ CN/79% CH₂ Cl₂ /1% MeOH) to give 190 mg of thetitle product (65%); IR(film) 3444 (br), 1724, 1368, 1246, 1174, 1096,1070, 1026, 988 cm⁻¹ ; ¹ H NMR (CDCl₃, 300 MHz) δ8.07 (d, J=7.2 Hz, 2H),7.59 (t, J=7.2 Hz, 1H), 7.47 (t, J=7.8 Hz, 2H), 7.35 (m, 5H), 6.65 (s,1H), 6.17 (t, J=8.7 Hz, 1H), 5.65 (d, J=6.6 Hz, 1H), 5.39 (bd, J=9.6 Hz,1H), 5.26 (bd, 1H), 4.93 (d, J=8.4 Hz, 1H), 4.67 (m, 3H), 4.28 (m, 5H),3.83 (d, J=6.0 Hz, 1H), 3.44 (d, J=5.1 Hz, 1H), 2.77 (m, 1H), , 2.50 (m,1H), 2.36 (s, 3H), 2.29 (d, J=8.4 Hz, 2H), 2.13 (bs, 3H), 2.01 (s, 3H),1.82 (m, 2H), 1.74 (s, 3H), 1.33 (s, 9H), 1.18 (s, 3H), 1.16 (s, 3H); ¹³C NMR (CDCl₃, 75.5 MHz) δ201.5, 171.7, 170.3, 167.0, 155.4, 141.3,133.7, 132.7, 130.2, 129.0, 128.8, 128.7, 128.1, 126.8, 83.8, 81.3,80.2, 78.6, 75.0, 74.4, 74.0, 73.6, 72.3, 60.6, 57.4, 56.2, 47.2, 43.2,35.3, 32.6, 28.2, 26.5, 22.6, 21.0, 15.5, 14.7, 10.8.

FABMS (NOBA) M+Na calcd for C₄₇ H₅₉ NO₁₆ SNa 948. Found: 948.

Example 173'-N-debenzoyl-3'-N-(t-butoxycarbonyl)-7-O-methylthiomethyl-3'-desphenyl-3'-isobutenylpaclitaxel##STR95##

To a solution of 7-O-methylthiomethylbaccatin III (1.5 g, 2.3 mmol) in30 mL of THF was added n-BuLi (1.0 mL, 2.5M in hexane, 2.5 mmol) at -60°C. and stirred for 10 minutes. Then a solution of(±)-cis-3-triethylsilyloxy-4-isobutenyl-N-t-butoxycarbonylazetidin-2-one(3.3 g, 9.3 mmol) in 10 mL of THF was added dropwise. The solution wasthen stirred at 0° C. for 30 min. and quenched with sat. NH₄ Cl solutionand extracted with ethyl acetate. The solution was dried over MgSO₄ andconcentrated and the residue chromatographed over silica gel (3:1hexane/ethyl acetate). The product was dissolved in 100 mL of THF andwas shaken with Bu₄ NF (2.3 mL, 1.0M in THF, 2.3 mmol) diluted withethyl acetate and washed with brine. The solution was dried over MgSO₄and concentrated and the residue chromatographed over silica gel (1.5:1hexane/ethyl acetate) to give 1.6 g of the title product (78%); IR(film)3452 (br), 1724, 1370, 1242, 1096, 1066 cm⁻¹ ; ¹ H-NMR (CDCl₃, 300 MHz)δ 8.07 (d, J=7.2 Hz, 2H), 7.59 (t, J=7.5 Hz, 1H), 7.45 (t, J=7.8 Hz,2H), 6.54 (s, 1H), 6.11 (t, J=9.3 Hz, 1H), 5.66 (d, J=6.0 Hz, 1H), 5.29(d, J=6.0 Hz, 1H), 4.94 (d, J=8.1 Hz, 1H), 4.75 (m, 2H), 4.64 (ABq,J=12.0, 2.7 Hz, 2H), 4.29 (m, 2H), 4.20 (m, 2H), 3.86 (d, J=6.0 Hz, 1H),3.37 (bd, 1H), 2.79 (m, 1H), 2.35 (s, 6H), 2.16 (s, 3H), 2.10 (s, 3H),2.04 (s, 3H), 1.82 (m, 1H), 1.74 (s, 9H), 1.34 (s, 9H), 1.23 (s, 3H),1.20 (s, 3H); ¹³ C NMR (CDCl₃, 75.5 Hz) δ202, 170.2, 169.2, 166.9,155.4, 140.6, 138.0, 133.7, 133.1, 130.1, 129.2, 128.6, 120.6, 83.8,81.2, 79.9, 78.7, 77.2, 76.1, 75.5, 74.6, 74.0, 73.7, 72.2, 57.4, 51.5,47.1, 43.2, 35.4, 32.9, 28.2, 26.4, 25.8, 22.4, 21.0, 18.6, 15.1, 14.8,10.9.

FABMS (NOBA) M+H calcd for C₄₅ H₆₂ NSO₁₅ 888. Found: 888.

Example 18 7-O-methylthiomethyl-3'-desphenyl-3'-isobutenylpaclitaxel

The title compound was prepared as in Example 17 from7-O-methylthiomethylbaccatin III and(±)-cis-3-triethylsilyloxy-4-isobutenyl-N-benzoylazetidin-2-one.

Example 193'-Desphenyl-3'-(2-furyl)-2'-O-ethyloxycarbonyl-7-O-methylthiomethylpaclitaxel

The title compound can be prepared from(3R,4R)-1-benzoyl-4-(2-furyl)-3-triethylsilyloxy-2-azetidinone and7-O-methylthiomethylbaccatin III following the procedures decribed inExamples 7(a) and 7(b).

Example 20 2'-O-n-propylcarbonyl-7-O-phosphonooxymethylpaclitaxel (a)Preparation of 2'-O-n-propylcarbonylpaclitaxel ##STR96##

To a solution of paclitaxel (15.0 g, 17.5 mmol) and diisopropylethylamine (18.3 mL, 105 mmol) in dichloromethane (175 mL) cooled to 0° C.was added butyryl chloride (5.49 mL, 52.4 mmol) dropwise over 2 min. Thereaction mixture was then warmed to room temperature and stirred for16h. The reaction mixture was then partitioned between ethyl acetate anda saturated aqueous ammonium chloride solution. The organic phase wasthen washed with a saturated sodium bicarbonate solution followed bybrine, dried over sodium sulfate and concentrated in vacuo. The residualoil was purified using flash chromatography (eluted with hexanes:ethylacetate) to provide the title ester (15.9 g, 98% yield) as a whitesolid; ¹ H-NMR (CDCl₃, 300 MHz) δ8.13-8.05 (2H, m), 7.75-7.65 (2H, m),7.62-7.30 (11H, m), 6.88 (1H, d, J=9.0 Hz), 6.26 (1H, s), 6.23 (1H, dd,J=8.4 Hz), 5.92 (1H, dd, J=9.3, 6.0 Hz), 5.65 (1H, d, J=7.1 Hz), 5.48(1H, d, J=3.2 Hz), 4.94 (1H, d, J=7.9 Hz), 4.21 (1H, dd, J=10.4, 6.5Hz), 4.28 (1H, d, J=8.4 Hz), 4.17 (1H, d, J=8.4 Hz), 3.78 (1H, d, J=7.0Hz), 2.64-1.02 (26H, m, including singlets at 2.43, 2.19, 1.91, 1.65,1.65, 1.20, 1.10, 3H each), 0.87 (3H, dd, J=8.2 Hz).

(b) Preparation of 2'-O-n-propylcarbonyl-7-O-methylthiomethylpaclitaxel##STR97##

To a solution of 2'-O-n-propylcarbonylpaclitaxel (14.4 g, 15.6 mmol) anddimethyl sulfide (9.23 mL, 124.8 mmol) in acetonitrile (312 mL) cooledto -40° C. was added benzoyl peroxide (15.1 g, 62.3 mmol) and thereaction mixture was warmed to room temperature over 1 h. At this time aTLC (eluted with hexanes:ethyl acetate, 1:1) indicated the reaction wascomplete. The reaction mixture was then diluted with ethyl acetate andthe resulting organic solution was washed three times with a saturatedsodium bicarbonate solution then brine. The organic phase was then driedover sodium sulfate and concentrated in vacuo. The 5 residual oil waspurified via flash chromatography (eluted with hexanes:ethyl acetate) toprovide the title compound (14.4 g, 93%) as a white solid; ¹ H-NMR(CDCl₃, 300 MHz) δ8.21-8.19 (2H, m), 7.72-7.70 (2H, m), 7.62-7.26 (11H,m), 6.92 (3H, s), 6.20 (1H, dd, J=8.4 Hz), 5.92 (1H, dd, J=9.0, 3.1 Hz),5.66 (1H, d, J=6.9 Hz), 5.51 (1H, d, J=3.2 Hz), 4.92 (1H, d, J=8.2 Hz),4.68-4.59 (2H, m), 4.32-4.26 (2H, m), 4.15 (1H, d, J=8.3 Hz), 3.86 (1H,d, J=6.8 Hz), 2.77 (1H, m), 2.50-1.05 (25H, m), 0.87 (3H, dd, J=7.3 Hz).

(c) Preparation of2'-O-n-propylcarbonyl-7-O-(dibenzylphosphonooxymethyl)paclitaxel##STR98##

N-Iodosuccinimide (4.9 g, 21.8 mmol) was added in one portion to asolution of 2'-O-n-propylcarbonyl-7-O-methylthiomethylpaclitaxel (10.7g, 11.0 mmol), dibenzylphosphate (15.3 g, 55.0 mmol) and 5 g of ovendried 3 Angstrom sieves in THF (200 mL) at room temperature and theresulting mixture was stirred for 1 h. At this time a TLC analysis(eluted with hexanes:ethyl acetate, 1:1) indicated the reaction wascomplete. The reaction mixture was then diluted to twice the initialvolume with ethyl acetate and filtered through a bed of celite. Thefiltrate was then poured into a saturated sodium bicarbonate solutioncontaining 1% sodium thiosulfate by weight. The organic layer was thenwashed four times with a saturated aqueous sodium bicarbonate solutionfollowed by brine. The aqueous layer was then back extracted with ethylacetate and the combined organics were dried over sodium sulfate andconcentrated in vacuo. The residual oil was purified via flashchromatography (hexanes:ethyl acetate) to provide the titledibenzylphosphate (9.9 g, 76% yield) as a white solid; ¹ H-NMR (CDCl₃,300 MHz) δ8.10-8.08 (2H, m), 7.74-7.71 (2H, m), 7.61-7.25 (21H, m), 6.94(1H, d, J=9.0 Hz), 6.31 (1H, s), 6.20 (1H, dd, J=8.7 Hz), 5.91 (1H, dd,J=9.0, 3.1 Hz), 5.64 (1H, d, J=6.9 Hz), 5.49 (1H, d, J=3.0 Hz), 5.39(1H, dd, J=6.6 Hz), 5.05-4.98 (5H, m), 4.86 (1H, d, J=8.4 Hz), 4.26-4.12(3H, m), 3.84 (1H, d, J=6.8 Hz), 2.82-2.71 (1H, m), 2.52-1.05 (26 H, m,including singlets at 2.43, 2.18, 1.97, 1.69, 1.22, 1.20, 3H each)0.90-0.85 (3H, dd, J=7.3 Hz).

(d) Preparation of2'-O-n-propylcarbonyl-7-O-phosphonooxymethylpaclitaxel ##STR99##

To a nitrogen purged Parr hydrogenation vessel was added 2.5 g of 10%palladium-on-carbon followed by neat ethyl acetate (150 mL) and asolution of2'-O-n-propylcarbonyl-7-O-(dibenzylphosphonooxymethyl)paclitaxel (4.9 g,4.14 mmol) in ethyl acetate (40 PAL). The reaction vessel was then fixedto a Parr hydrogenator, placed under vacuum, then pressurized with ahydrogen atmosphere of 50 psi. The heterogenous mixture was then shakenfor 5 h after which time a TLC analysis (eluted with hexanes:ethylacetate) indicated the consumption of starting material. The reactionmixture was then placed under vacuum and subsequently purged withnitrogen. The mixture was then filtered using a sintered glass funneland the filtrate concentrated in vacuo to provide the title compound(3.7 g, 91% yield) which was pure by ¹ H-NMR analysis.

(e) Preparatin of 2'-O-n-propylcarbonyl-7-O-phosphonooxymethylpaclitaxeltriethanolamine salt

To a solution of 2'-O-n-propylcarbonyl-7-O-phosphonooxymethylpaclitaxel(1.1 g, 1.09 mmol) in dichloromethane (50 mL) was added a 0.1M solutionof triethanolamine (10.9 mL, 1.09 mL) in ethyl acetate and the resultingmixture was stirred for 5 min at room temperature. The reaction mixturewas then concentrated in vacuo and the resulting white solid waspurified by first dissolving the crude material in a minimum amount of amethylene chloride-ethyl acetate mixture. Hexanes were then added tothis solution and the desired amine salt precipitated as a white solid.The mixture was then decanted to provide the amine salt as a white solidwhich had an observed HPLC purity greater than 95%; ¹ H-NMR (Acetone-d₆,D₂ O, 300 MHz) δ8.09-8.07 (2H, m), 7.86-7.84 (2H), 7.69-7.24 (11H, m),7.24 (1H, dd, J=7.5 Hz), 6.36 (1H, s), 6.05 (1H, dd, J=8.4 Hz), 5.85(1H, d, J=6.7 Hz), 5.61 (1H, d, J=7.0 Hz), 5.49 (1H, d, J=6.9 Hz),5.15-5.13 (1H, m), 4.98 (1H, d, J=8.2 Hz), 4.87 (1H, dd, J=12.1 Hz, 6.4Hz), 4.12 (bs, 2H), 3.89-3.80 (7H, m), 3.36-3.30 (6H, m), 2.95-2.93 (1H,m), 2.42-1.50 (25H, m, including singlets at 2.42, 2.22, 1.93, 1.66, 3Heach), 1.13 (bs, 6H), 0.86-0.81 (2H, dd, J=7.4 Hz).

Example 21.2'-O-Methylcarbonyl-7-O-phosphonooxymethylpaclitaxel (a)Preparation of 2'-O-acetylpaclitaxel ##STR100##

To a solution of paclitaxel (8.0 g, 9.37 mmol) and diisopropylethylamine (4.89 mL, 28.1 mmol) in dichloromethane (140 mL) cooled to 0° C.was added acetyl chloride (1.0 mL, 14.1 mmol) dropwise over 2 min. Thereaction mixture was then warmed to room temperature and stirred for10h. The reaction mixture was then partitioned between ethyl acetate anda saturated aqueous ammonium chloride solution. The organic phase wasthen washed with a saturated sodium bicarbonate solution followed bybrine, dried over sodium sulfate and concentrated in vacuo. The residualoil was purified using flash chromatography (eluted with hexanes:ethylacetate) to provide 2'-O-acetylpaclitaxel (7.7 g, 92%) as a white solid;¹ H-NMR (CDCl₃, 300 MHz) δ8.10-8.08 (2H, m), 7.92-7.90 (1H, m),7.89-7.70 (2H, m), 7.60-7.29 (11H, m), 6.94 (1H, d, J=9.2 Hz), 6.26 (1H,s), 6.23 (1H, dd, J=9.5 Hz), 5.93 (1H, dd, J=9.2, 3.1 Hz), 5.65 (1H, d,J=7.0 Hz), 5.48 (1H, d, J=3.2 Hz), 4.94 (1H, d, J=7.8 Hz), 4.42 (1H, dd,J=10.8 Hz, 6.6 Hz), 4.28 (1H, d, J=8.4 Hz), 4.16 (1H, d, J=8.4 Hz), 3.78(1H, d, J=6.9 Hz), 2.60-1.02 (25H, m, including singlets at 2.42, 2.19,2.12, 1.90, 1.65, 1.25, 1.11, 3H each).

(b) Preparation of 2'-O-acetyl-7-O-methylthiomethylpaclitaxel ##STR101##

To a solution of 2'-O-acetylpaclitaxel (7.7 g, 8.60 mmol) and dimethylsulfide (5.1 mL, 68.8 mmol) in acetonitrile (200 mL) cooled to -40° C.was added benzoyl peroxide (8.3 g, 34.4 mmol) and the reaction mixturewas warmed to room temperature over 1 h. At this time a TLC (eluted withhexanes:ethyl acetate, 1:1) indicated the reaction was complete. Thereaction mixture was then diluted with ethyl acetate and the resultingorganic solution was washed three times with a saturated sodiumbicarbonate solution then brine. The organic phase was then dried oversodium sulfate and concentrated in vacuo. The residual oil was purifiedvia flash chromatography (hexanes:ethyl acetate) to provide the titlemethylthiomethylether (7.39 g, 90%) as a white solid; ¹ H-NMR (CDCl₃,300 MHz) δ8.10-8.08 (2H, m), 7.77-7.73 (2H, m), 7.65-7.26 (11H, m), 6.53(3H, 2), 6.20 (1H, dd, J=8.3 Hz), 5.92 (1H, dd, J=12.2, 3.1 Hz), 5.67(1H, d, J=7.0 Hz), 5.51 (1H, d, J=3.2 Hz), 4.94 (1H, d, J=8.2 Hz),4.69-4.60 (3H, m), 4.33-4.28 (2H, m), 4.27 (1H, d, J=8.4 Hz), 3.86 (1H,d, J=6.9 Hz), 2.84-2.74 (1H, m), 2.50-1.1 (28H, m, including singlets at2.41, 2.15, 2.13, 2.11, 2.06, 1.73, 1.18, 1.15, 3H each).

(c) Preparation of2'-O-acetyl-7-O-(dibenzylphosphonooxymethyl)paclitaxel ##STR102##

N-Iodosuccinimide (1.75 g, 7.85 mmol) was added in one portion to asolution of 2'-O-acetyl-7-O-methylthiomethylpaclitaxel (5.0 g, 5.23mmol), dibenzylphosphate (7.3 g, 26.1 mmol) and 5 g of oven dried 3Angstrom sieves in THF (104 mL) at room temperature and the resultingmixture was stirred for 1.5 h. At this time a TLC analysis (eluted withhexanes:ethyl acetate, 1:1) indicated the reaction was complete. Thereaction mixture was then diluted to twice the volume with ethyl acetateand filtered through a bed of celite. The filtrate was then poured intoa saturated sodium bicarbonate solution containing 1% sodium thiosulfateby weight. The organic layer was then washed four times with a saturatedaqueous sodium bicarbonate solution followed by brine. The aqueouslayers were then back extracted with ethyl acetate and the combinedorganics were dried over sodium sulfate and concentrated in vacuo. Theresidual oil was purified via flash chromatography (eluted withhexanes:ethyl acetate) to provide the title dibenzylphosphate (4.9 g,80%) as a white solid.

(b) Preparation of 2'-O-acetyl-7-O-phosphonooxymethylpaclitaxel##STR103##

To a nitrogen purged Parr hydrogenation vessel was added 700 mg of 10%palladium-on-carbon followed by neat ethyl acetate (130 mL) and asolution of 2'-O-acetyl-7-O-(dibenzylphosphonooxymethyl)paclitaxel (1.0g, 0.84 mmol) in ethyl acetate (40 mL). The reaction vessel was thenfixed to a Parr hydrogenator, placed under vacuum, then pressurized witha hydrogen atmosphere of 50 psi. The reaction mixture was then shakenfor 6 h after which time a TLC analysis (eluted with hexanes:ethylacetate) indicated the consumption of the starting material. Thereaction mixture was then placed under vacuum and subsequently purgedwith nitrogen. The heterogenous solution was then filtered using asintered glass funnel and the filtrate concentrated in vacuo to providea white solid (848 mg) which ¹ H-NMR analysis showed to be a mixture ofthe desired title compound (50%) and 2'-O-acetylpaclitaxel.

(e) Preparation of 2'-O-acetyl-7-O-phosphonooxymethylpaclitaxeltriethanolamine salt

To a solution of 2'-O-acetyl-7-O-phosphonooxymethylpaclitaxel (424 mg,0.42 mmol) and the aforementioned side product 2'-O-acetylpaclitaxel indichloromethane (15 mL) was added a 0.1M solution of triethanolamine(3.7 mL, 3.8 mmol) in ethyl acetate and the resulting mixture wasstirred for 10 min at room temperature. The reaction mixture was thenconcentrated in vacuo and the resulting white solid was purified by C18chromatography (water:acetonitrile 2.3:1) to provide the desired aminesalt (310 mg, 72%) which had an observed HPLC purity greater than 96%; ¹H-NMR (Acetone-d₆, D₂ O, 300 MHz) δ8.08-8.05 (2H, m), 7.86-7.83 (2H, m),7.69-7.24 (11H, m), 7.23 (1H, dd, J=7.4 Hz), 6.35 (1H, s), 6.02 (1H, dd.J=8.3 Hz), 5.79 (1H, d, J=6.9 Hz), 5.59 (1H, d, J=7.1 Hz), 5.45 (1H, d,J=6.9 Hz), 5.12 (1H, dd, J=6.4 Hz), 4.95 (1H, d, J=8.4 Hz), 4.86 (1H,dd, J=11.5, 6.5 Hz), 4.24-4.18 (1H, m), 4.12 (2H, bs), 3.92-3.89 (6H,m), 3.80-3.77 (1H, m), 3.46-3.43 (6H, m), 3.00-2.89 (1H, m), 2.39-1.65(21H including singlets at 2.39, 2.14, 2.12, 1.92, 1.65, 1.11 3H each)1.11 (6H, bs).

Example 22 2'-O-methoxycarbonyl-7-O-phosphonooxymethylpaclitaxel (a)Preparation of 2'-O-methoxycarbonylpaclitaxel ##STR104##

To a solution of paclitaxel (8.0 g, 9.60 mmol) and diisopropylethylamine (5.0 mL, 28.8 mmol) in dichloromethane (96 mL) cooled to 0° C. wasadded chloromethyl carbonate (1.11 mL, 14.4 mmol) dropwise over 2 min.The reaction mixture was then warmed to room temperature and stirred for20 h. The reaction mixture was then partitioned between ethyl acetateand a saturated aqueous ammonium chloride solution. The organic phasewas then washed with a saturated sodium bicarbonate solution, followedby brine, dried over sodium sulfate and concentrated in vacuo. Theresidual oil was purified using flash chromatography (hexanes:ethylacetate) to provide the title compound (7.8 g, 91.3%) as a white solid;¹ H-NMR (CDCl₃, 300MHz) δ8.12-8.09 (2H, m), 7.72-7.70 (2H, m), 7.62-7.30(11H, m), 6.96 (1H, d, J=9.3 Hz), 629-6.23 (3H, m), 5.95 (1H, dd, J=9.3,2.5 Hz), 5.66 (1H, d, J=7.1 Hz), 5.38 (1H, d, J=2.6 Hz), 4.94 (1H, d,J=7.8 Hz), 4.41 (1H, dd, J=10.8, 6.6 Hz), 4.28 (1H, d, J=8.4 Hz), 4.17(1H, d, J=8.4 Hz), 3.79-3.78 (3H, m), 2.60-1.04 (22H, m, includingsinglets at 2.43, 2.19, 1.90, 1.65, 1.22, 1.10, 3H each).

(b) Preparation of 2'-O-methoxycarbonyl-7-O-methylthiomethylpaclitaxel##STR105##

To a solution of 2'-O-methoxycarbonylpaclitaxel (7.4 g, 8.10 mmol) anddimethyl sulfide (4.8 mL, 64.8 mmol) in acetonitrile (162 mL) cooled to-40° C. was added benzoyl peroxide (7.48 g, 32.4 mmol) and the reactionmixture was warmed to room temperature over 1 h. At this time a TLCanalysis (eluted with hexanes:ethyl acetate, 1:1) indicated the reactionwas complete. The reaction mixture was then diluted with ethyl acetateand the resulting organic solution was washed three times with asaturated sodium bicarbonate solution then brine. The organic phase wasthen dried over sodium sulfate and concentrated in vacuo. The residualoil was purified via flash chromatography (eluted with hexanes:ethylacetate) to provide the title compound (7.4 g, 95%) as a white solid; ¹H-NMR (CDCl₃, 300 MHz) δ8.25-8.23 (2H, m), 7.87-7.77 (2H, m), 7.60-7.30(11H, m), 6.93 (1H, d, J=9.2 Hz), 6.53 (1H, s), 6.25 (1H, dd, J=8.2 Hz),5.95 (1H, dd, J=11.7, 2.4 Hz), 5.68 (1H, d, J=6.9 Hz), 5.40 (1H, d,J=2.6 Hz), 4.95 (1H, d, J=8.1 Hz), 4.69-4.60 (2H, m), 4.31-4.26 (2H, m),4.16 (1H, d, J=8.4 Hz), 3.86 (1H, J=6.9 Hz), 3.79 (3H, s), 2.84-2.74(1H, m), 2.43-1.10 (25H, including singlets at 2.44, 2.15, 2.10, 2.08,1.73, 1.19, 1.16 3H).

(c) Preparation of2'-O-methoxycarbonyl-7-O-(dibenzylphosphonooxymethyl)paclitaxel##STR106##

N-Iodosuccinimide (1.74 g, 7.77 mmol) was added in one portion to asolution of 2'-O-methoxycarbonylpaclitaxel (5.04 g, 5.18 mmol),dibenzylphosphate (7.2 g, 25.8 mmol) and 5 g of oven dried 3 Angstromsieves in THF (100 mL) at room temperature and the resulting mixture wasstirred for 1.5 h. At this time a TLC analysis (eluted withhexanes:ethyl acetate, 1:1) indicated the reaction was complete. Thereaction mixture was then diluted to twice the volume with ethyl acetateand filtered through a bed of celite. The filtrate was then poured intoa saturated sodium bicarbonate solution containing 1% sodium thiosulfateby weight. The organic layer was then washed four times with a saturatedaqueous sodium bicarbonate solution followed by brine. The aqueous layerwas then back extracted with ethyl acetate and the combined organicswere dried over sodium sulfate and concentrated in vacuo. The residualoil was purified via flash chromatography (eluted with hexanes:ethylacetate) to provide the title compound (5.1 g, 96%) as a white solid; ¹H-NMR (CDCl₃, 300 MHz) δ8.12-8.08 (2H, m), 7.73-7.70 (2H, m), 7.62-7.27(21H, m), 7.00 (1H, d, J=9.2 Hz), 6.31 (1H, s), 6.24-6.21 (1H, m),5.96-5.92 (1H, m), 5.66-5.64 (1H, m), 5.40-5.36 (2H, m), 5.05-4.93 (5H,m), 4.87-4.84 (1H, m), 4.29-4.05 (3H, m), 3.85-3.83 (1H, m), 3.77 (3H,s), 2.81-2.71 (1H, m), 2.62-1.05 (22H, m, including singlets at 2.43,2.19, 2.01, 1.73, 1.22, 1.15, 3H each).

(d) Preparation of 2'-O-methoxycarbonyl-7-O-phosphonooxymethylpaclitaxel##STR107##

To a nitrogen purged Parr hydrogenation vessel was added 1.3 g of 10%palladium-on-carbon followed by neat ethyl acetate (140 mL) and asolution of2'-O-methoxycarbonyl-7-O-(dibenzylphosphonooxymethyl)paclitaxel (3.4 g,3.32 mmol) in ethyl acetate (40 mL). The reaction vessel was then fixedto a Parr hydrogenator, placed under vacuum, then pressurized with ahydrogen atmosphere of 50 psi. The resulting mixture was shaken for 8.5h after which time a TLC analysis (eluted with hexanes:ethyl acetate)indicated the consumption of starting material. The reaction mixture wasthen placed under vacuum and subsequently purged with nitrogen. Theheterogenous solution was then filtered using a sintered glass funneland the filtrate concentrated in vacuo to provide a white solid (2.9 g)which ¹ H-NMR analysis showed to be a mixture of the desired titleproduct (67%) and 2'-O-methoxycarbonylpaclitaxel (33%).

(e) Preparation of 2'-O-methoxycarbonyl-7-O-phosphonooxymethylpaclitaxeltriethanolamine salt

To a solution of 2'-O-methoxycarbonyl-7-O-phosphonooxymethylpaclitaxel(1.91 g, 1.87 mmol) and the aforementioned side product2'-O-methoxycarbonylpaclitaxel in dichloromethane (11 mL) was added a0.1M solution of triethanolamine (18.9 mL, 1.89 mmol) in ethyl acetateand the resulting mixture was stirred for 5 min at room temperature. Thereaction mixture was then concentrated in vacuo and the resulting whitesolid was purified by C18 chromatography (eluted with water:acetonitrile2.3:1) to provide after subsequent lyophilization the triethanolaminesalt which had an observed HPLC purity greater than 97%; ¹ H-NMR(Acetone-d₆, D₂ O, 300 MHz) δ8.08-8.06 (2H, m), 7.88-7.55 (2H, m),7.69-7.24 (11H, m), 7.24 (1H, dd, J=7.3 Hz), 6.36 (1H, m), 6.05 (1H, dd,J=8.8 Hz), 5.82 (1H, d, J=6.8 Hz), 5.60 (1H, d, J=7.1 Hz), 5.46 (1H, d,J=6.9 Hz), 5.13 (1H, dd, J=6.5 Hz), 5.98 (1H, d, J=8.1 Hz), 4.87 (1H,dd, J=11.8 Hz, 6.3 Hz), 4.21 (1H, dd, J=10.3, 6.9 Hz), 4.13 (bs, 6H),3.92-3.89 (6H, m), 3.81 (1H, d, J=7.02), 3.76 (3H, s), 3.46-3.42 (6H,m), 3.01-2.90 (1H, m), 2.42 (3H, s), 2.20-1.80 (10H, including singletsat 2.20, 1.93), 1.66 (3H, s), 1.12 (6H, bs).

Example 23 Preparation ofphosphonooxymethoxymethyl-7-O-phosphonooxymethylpaclitaxel (a)Preparation of 2'-O-methylthiomethoxymethylpaclitaxel ##STR108##

Palladium (10%) on carbon (3 g) was added to a solution of2'-O-methylthiomethoxymethyl-7-O-benzyloxycarbonylpaclitaxel (1.2 g,1.11 mmol) in ethyl acetate (100 mL) and ethanol (70 mL) housed in aParr bottle. The vessel was affixed to a Parr apparatus and the reactionmixture subjected to hydrogen at 50 psi. The reaction mixture was shakenfor 20.5 h, then filtered using a sintered glass funnel. The filtratewas concentrated in vacuo and the residual oil purified via flashchromatography (eluted with hexanes:ethyl acetate) to provide thedesired (0.98 g, 93%) as a solid. ¹ H-NMR (CDCl₃, 300 MHz), δ8.12-8.10(2H, m), 7.76-7.73 (2H, m),7.61-7.27 (11H, m), 7.03 (1H, d, J=8.9 Hz),6.40-6.27 (1H, m), 6.25 (1H, s), 5.80 (1H, dd, J=8.9, 2.4 Hz), 5.66 (1H,d, J=7.1 Hz), 4.98-4.94 (1H, m), 4.86-4.79 (2H, m), 4.75-4.68 (1H, Ira),4.43-4.39 (1H, m), 4.31-4.26 (2H, m), 4.05 (1H, d, J=11.7 Hz), 3.78 (1H,d, J=7.1 Hz), 2.60-1.06 (25H, m, including singlets at 2.45, 2.21, 2.02,1.85, 1.66, 1.22, 1.11, 3H each).

(b) Preparation of2'-O-methylthiomethoxymethyl-7-O-methylthiomethylpaclitaxel ##STR109##

To a solution of 2'-O-methylthiomethoxymethylpaclitaxel. (0.98 g, 1.03mmol) and dimethyl sulfide (0.6 mL, 8.11 mmol) in acetonitrile (20 mL)cooled to -40° C. was added benzoyl peroxide (1.0 g, 4.13 mmol) and thereaction mixture was warmed to room temperature over 30 min. At thistime a TLC analysis (eluted with hexanes:ethyl acetate, 1:1) indicatedthe reaction was complete. The reaction mixture was then diluted withethyl acetate and the resulting organic solution was washed three timeswith a saturated sodium bicarbonate solution then brine. The organicphase was then dried over sodium sulfate and concentrated in vacuo. Theresidual oil was purified via flash chromatography (eluted withhexanes:ethyl acetate) to provide the title product (0.945 g, 91%) as awhite solid; ¹ H-NMR (CDCl₃, 300 MHz) δ8.13-8.11 (2H, m), 7.79-7.77 (2H,m), 7.61-7.29 (11H, m), 6.54 (1H, s), 6.30-6.26 (1H, m), 5.83-5.80 (1H,m), 5.71-5.69 (1H, m), 5.01-4.66 (6H, m), 4.34-4.04 (5H, m), 3.88 (1H,d, J=6.6 Hz), 2.90-2.80 (1H, m), 2.55-1.05 (27H, m, including singletsat 2.51, 2.18, 2.11, 1.80, 1.21, 1.20, 3H each).

(c) Preparation of2'-O-dibenzylphosphonooxymethoxymethyl-7-O-(dibenzylphosphonooxymethyl)paclitaxel##STR110##

N-Iodosuccinimide (0.615 g, 2.74 mmol) was added in one portion to asolution 2'-O-methylthiomethoxymethyl-7-O-methylthiomethylpaclitaxel(0.92 g, 0.916 mmol), dibenzylphosphate (2.03 g, 7.30 mmol) and 1 g ofoven dried 3 Angstrom sieves in THF (18 mL) at room temperature and theresulting mixture was stirred for 30 min. At this time a TLC analysis(eluted with hexanes:ethyl acetate, 1:2) indicated the reaction wascomplete. The reaction mixture was then diluted to twice the volume withethyl acetate and filtered through a bed of celite. The filtrate wasthen poured into a saturated sodium bicarbonate solution containing 1%sodium thiosulfate by weight. The organic layer was then washed fourtimes with a saturated aqueous sodium bicarbonate solution followed bybrine. The aqueous layer was then back extracted with ethyl acetate andthe combined organics were dried over sodium sulfate and concentrated invacuo. The residual oil was purified via flash chromatography (elutedwith hexanes:ethyl acetate) to provide the title product (0.768 g, 58%)as a white solid; ¹ H-NMR (CDCl₃, 300 MHz) δ8.10-8.05 (2H, m), 7.80-7.74(2H, m), 7.65-7.27 (11H, m), 6.30 (1H, s), 6.25-6.18 (1H, m), 5.82 (1H,dd, J=9.1, 3.4 Hz), 5.63 (1H, dd, J=6.9 Hz), 5.38 (1H, dd, J=6.6 Hz),5.10-4.60 (15H, m), 4.30-4.10 (3H, m), 3.80 (1H, d, J=6.8 Hz), 2.85-2.65(1H, m), 2.50-1.60 (22H, m, including singlets at 2.47, 2.16, 1.91,1.72, 1.88, 1.15, 3H each).

(d) Preparation of2'-O-phosphonooxymethoxymethyl-7-O-phosphonooxymethylpaclitaxel##STR111##

To a nitrogen purged Parr hydrogenation vessel was added 1.3 g of 10%palladium-on-carbon followed by neat ethyl acetate (110 mL) and asolution of2'-O-dibenzylphosphonooxymethoxymethyl-7-O-(dibenzylphosphonooxymethyl)paclitaxel(0.721 g, 0.498 mmol) in ethyl acetate (40 mL). The reaction vessel wasthen fixed to a Parr hydrogenator, placed under vacuum then pressurizedwith a hydrogen atmosphere of 50 psi. The heterogenous mixture was thenshaken for 16 h after which time a TLC analysis (eluted withhexanes:ethyl acetate) indicated the consumption of starting material.The reaction mixture was then placed under vacuum and subsequentlypurged with nitrogen. The mixture was then filtered using a sinteredglass funnel and the filtrate concentrated in vacuo to provide the titleproduct (0.413 g) which was at 60% purity by HPLC analysis.

(e) Preparation of2'-O-phosphonooxymethoxymethyl-7-O-phosphonooxymethylpaclitaxelbis-triethanolamine salt

To a solution of crude of2'-O-phosphonooxymethoxymethyl-7-O-phosphonooxymethylpaclitaxel (413 mg)in dichloromethane (10 mL) was added a 0.1M solution of triethanolamine(7.6 mL, 0.076 mmol) in ethyl acetate and the resulting mixture wasstirred for 5 min at 5 room temperature. The reaction mixture was thenconcentrated in vacuo and the resulting white solid was purified by C18chromatography (eluted with water:acetonitrile, 9:1 to 5.6:1). Fractionsof eluent containing the desired salt in greater than 96% purity by HPLCwere combined and the acetonitrile was removed via rotary evaporation.The resulting aqueous solution of the amine salt was lyophylized toprovide the desired salt (0.210 g, 30% over 2 steps) as a white solid. ¹H- NMR (Acetone-d₆, D₂ O, 300 MHz) δ7.97-7.94 (2H, m), 7.79-7.76 (2H,m), 7.67-7.33 (11H, m), 7.12-7.07 (1H, m), 6.26 (1H, s), 5.89 (1H, dd,J=8.6 Hz), 5.48 (1H, d, J=7.9 Hz), 5.00-4.79 (8H, m), 4.70 (1H, d, J=8.1Hz), 4.15-4.03 (3H, m), 3.74-3.66 (7H, m), 3.14-2.86 (8H, m), 2.33-1.00(20H, m, including singlets at 2.33, 2.10, 1.88, 1.56, 1.02, 1.00, 3Heach).

ADDITIONAL EXAMPLES

The general procedures provided in the foregoing examples anddescriptions are followed in the preparation of the following compoundswithin the scope of formula (A).

    __________________________________________________________________________    III                                                                            ##STR112##                                                                   R.sup.I       R.sup.II '                                                                       R.sup.II      R.sup.III     R.sup.IV   R.sup.V               __________________________________________________________________________    OH            H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           Ph         4-FPh                                                                         4-CH.sub.3 Ph                                                                 2-furanyl                                                                     2-thienyl                                                                     (CH.sub.3).sub.2                                                              CH                                                                            isobutenyl                                                                    (2-methyl-1-                                                                  propenyl)                                                                     *c-C.sub.3                                                                    H.sub.6                                                                       3-furanyl                                                                     3-thienyl                                                                     2-propenyl            OCH.sub.2 OP(O)(OH).sub.2                                                                   H  OH            AcO           Ph         4-CF.sub.3 Ph                                                                 2-furanyl                                                                     (CH.sub.3).sub.2                                                              CH                                                                            2-thienyl                                                                     isobutenyl                                                                    cyclopropyl                                                                   3-thienyl                                                                     3-furanyl                                                                     2-propenyl                                                                    iosopropyl            CH.sub.3 CH.sub.2 OC(O)O                                                                    H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           Ph         4-FPh                                                                         2-thienyl                                                                     isopropyl                                                                     2-propenyl                                                                    isobutenyl                                                                    cyclopropyl                                                                   2-furanyl                                                                     3-furanyl                                                                     3-thienyl             OCH.sub.2 OP(O)(OH).sub.2                                                                   H  OH            OH            (CH.sub.3).sub.3 CO                                                                      Ph                                     H                                                                             CH.sub.3 CH.sub.2 OC(O)O                                     OH            H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OH            (CH.sub.3).sub.3 CO                                                                      Ph                    CH.sub.3 CH.sub.2 OC(O)O.sub.2                                                OCH.sub.2 OP(O)(OH).sub.2                                                                   H  H             AcO           Ph         Ph                                     CH.sub.3 CH.sub.2 OC(O)O                                     OH            H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           Ph         Ph                    CH.sub.3 OC(O)O                                                               CH.sub.3 CH.sub.2 OC(O)O                                                      CH.sub.3 (CH.sub.2).sub.2 OC(O)O                                              CH.sub.3 (CH.sub.2).sub.3 OC(O)O                                              CCl.sub.3 CH.sub.2 OC(O)O                                                     CH.sub.3 C(O)O                                                                CH.sub.3 CH.sub.2 (O)O                                                        CH.sub.3 (CH.sub.2).sub.2 C(O)O                                               CH.sub.3 (CH.sub.2).sub.3 C(O)O                                               PhC(O)O                                                                       PhOC(O)O                                                                      CH.sub.2 CHCH.sub.2 OC(O)O                                                    PhCH.sub.2 OC(O)O                                                             OH            H  OH            OCH.sub.2 OP(O)(OH).sub.2                                                                   Ph         Ph                    OH            H  H             OCH.sub.2 OP(O)(OH).sub.2                                                                   Ph         Ph                    OCH.sub.2 OP(O)(OH).sub.2                                                                   H  H             H             (CH.sub.3).sub.3 CO                                                                      4-CH.sub.3 OPh        OH            H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           (CH.sub.3).sub.3 CO                                                                      isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclobutyl                                                                    isopropyl             CH.sub.3 OC(O)O                                                                             H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           (CH.sub.3).sub.3 CO                                                                      isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclobutyl                                                                    isopropyl             CH.sub.3 CH.sub.2 OC(O)O                                                                    H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           (CH.sub.3).sub.3 CO                                                                      isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclobutyl                                                                    isopropyl             CH.sub.3 (CH.sub.2).sub.2 OC(O)O                                                            H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           (CH.sub.3).sub.3 CO                                                                      isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclobutyl                                                                    isopropyl             CH.sub.3 (CH.sub.2).sub.3 OC(O)O                                                            H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           (CH.sub.3).sub.3 CO                                                                      isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclobutyl                                                                    isopropyl             CCl.sub.3 CH.sub.2 OC(O)O                                                                   H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           (CH.sub.3).sub.3 CO                                                                      isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclobutyl                                                                    isopropyl             CH.sub.3 C(O)O                                                                              H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           (CH.sub.3).sub.3 CO                                                                      isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclobutyl                                                                    isopropyl             CH.sub.3 CH.sub.2 (O)O                                                                      H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           (CH.sub.3).sub.3 CO                                                                      isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclobutyl                                                                    isopropyl             CH.sub.3 (CH.sub.2).sub.2 C(O)O                                                             H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           (CH.sub.3).sub.3 CO                                                                      isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclobutyl                                                                    isopropyl             CH.sub.3 (CH.sub.2).sub.3 C(O)O                                                             H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           (CH.sub.3).sub.3 CO                                                                      isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclobutyl                                                                    isopropyl             PhC(O)O       H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           (CH.sub.3).sub.3 CO                                                                      isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclobutyl                                                                    isopropyl             PhOC(O)O      H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           (CH.sub.3).sub.3 CO                                                                      isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclobutyl                                                                    isopropyl             CH.sub.2 CHCH.sub.2 OC(O)O                                                                  H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           (CH.sub.3).sub.3 CO                                                                      isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclobutyl                                                                    isopropyl             PhCH.sub.2 OC(O)O                                                                           H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           (CH.sub.3).sub.3 CO                                                                      isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclobutyl                                                                    isopropyl             OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O 2-furanyl                                                                     3-furanyl                                                                     isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   cyclobutyl                                                                    3-thienyl                                                                     2-thienyl                                                                     isopropyl             OH            H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O 2-furanyl                                                                     3-furanyl                                                                     isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   cyclobutyl                                                                    3-thienyl                                                                     2-thienyl                                                                     isopropyl             OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           isopropyloxy                                                                             2-furanyl                                                                     3-furanyl                                                                     2-thienyl                                                                     isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   cyclobutyl                                                                    3-thienyl                                                                     isopropyl             OH            H  OCH.sub.2 OP(O)(OH).sub.2                                                                   AcO           isopropyloxy                                                                             2-furanyl                                                                     3-furanyl                                                                     2-thienyl                                                                     isobutenyl                                                                    2-propenyl                                                                    cyclopropyl                                                                   cyclobutyl                                                                    3-thienyl                                                                     isopropyl             OH            H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         AcO           (CH.sub.3).sub.3 CO                                                                      2-furanyl             CH.sub.3 OC(O)O                                                               CH.sub.3 CH.sub.2 OC(O)O                                                      CH.sub.3 (CH.sub.2).sub.2 OC(O)O                                              CH.sub.3 (CH.sub.2).sub.3 OC(O)O                                              CCl.sub.3 CH.sub.2 OC(O)O                                                     CH.sub.3 C(O)O                                                                CH.sub.3 CH.sub.2 (O)O                                                        CH.sub.3 (CH.sub.2).sub.2 C(O)O                                               CH.sub.3 (CH.sub.2).sub.3 C(O)O                                               PhC(O)O                                                                       PhOC(O)O                                                                      CH.sub.2 CHCH.sub.2 OC(O)O                                                    PhCH.sub.2 OC(O)O                                                             OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         AcO           (CH.sub.3).sub.3 CO                                                                      3-furanyl                                                                     isobutenyl                                                                    2-propenyl                                                                    2-thienyl                                                                     3-thienyl                                                                     cyclopropyl                                                                   isopropyl             OH            H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         AcO           (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                                     isobutenyl                                                                    2-thienyl                                                                     2-propenyl                                                                    isopropyl                                                                     cyclopropyl                                                                   3-thienyl                                                                     3-furanyl             OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         AcO           CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O 2-furanyl             OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         AcO           isopropyloxy                                                                             2-furanyl             OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OCO.sub.2 CH.sub.3                                                                          (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                                     3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclopropyl                                                                   isobutenyl                                                                    2-thienyl                                                                     2-propenyl            OH            H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OCO.sub.2 CH.sub.3                                                                          (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                                     3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclopropyl                                                                   isobutenyl                                                                    2-thienyl                                                                     2-propenyl            OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OMe           (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                                     3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclopropyl                                                                   isobutenyl                                                                    2-thienyl                                                                     2-propenyl            OH            H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OMe           (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                                     3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclopropyl                                                                   isobutenyl                                                                    2-thienyl                                                                     2-propenyl            OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OC(O)Ph       (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                                     3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclopropyl                                                                   isobutenyl                                                                    2-thienyl                                                                     2-propenyl            OH            H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OC(O)Ph       (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                                     3-furanyl                                                                     3-thienyl                                                                     isopropyl                                                                     cyclopropyl                                                                   isobutenyl                                                                    2-thienyl                                                                     2-propenyl            OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OCO.sub.2 CH.sub.3                                                                          Ph         2-furanyl                                                          CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O                                                                    isopropyloxy                     OH            H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OCO.sub.2 CH.sub.3                                                                          Ph         2-furanyl                                                          CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O                                                                    isopropyloxy                     OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OMe           Ph         2-furanyl                                                          CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O                                                                    isopropyloxy                     OH            H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OMe           Ph         2-furanyl                                                          CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O                                                                    isopropyloxy                     OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OC(O)Ph       Ph         2-furanyl                                                          CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O                                                                    isopropyloxy                     OH            H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OC(O)Ph       Ph         2-furanyl                                                          CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O                                                                    isopropyloxy                     OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OCO.sub.2 CH.sub.3                                                                          (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                          isopropyloxy                                                                  CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O                       OH            H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OCO.sub.2 CH.sub.3                                                                          (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                          isopropyloxy                                                                  CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O                       OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OMe           (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                          isopropyloxy                                                                  CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O                       OH            H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OMe           (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                          isopropyloxy                                                                  CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O                       OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OC(O)Ph       (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                          isopropyloxy                                                                  CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O                       OH            H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OC(O)Ph       (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                          isopropyloxy                                                                  CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O                       OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OCO.sub.2 CH.sub.3                                                                          (CH.sub.3).sub.3 CO                                                                      isobutenyl            OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OMe           (CH.sub.3).sub.3 CO                                                                      isobutenyl            OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OC(O)Ph       (CH.sub.3).sub.3 CO                                                                      isobutenyl            OH            H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OCO.sub.2 CH.sub.3                                                                          Ph         2-furanyl             OH            H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OMe           Ph         2-furanyl             OH            H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OC(O)Ph       Ph         2-furanyl             OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OCO.sub.2 CH.sub.3                                                                          (CH.sub.3).sub.3 CO                                                                      2-propenyl            OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OMe           (CH.sub.3).sub.3 CO                                                                      2-propenyl            OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OC(O)Ph       (CH.sub.3).sub.3 CO                                                                      2-propenyl            OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         H  OH            AcO           (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                                     2-thienyl                                                                     3-furanyl                                                                     3-thienyl                                                                     isobutenyl                                                                    2-propenyl                                                                    cyclopropyl           OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         H  OH            AcO           CH.sub.3 CH.sub.2 CH.sub.2                                                    CH.sub.2 O 2-furanyl                                                          isopropyloxy                                                                  (CH.sub.3).sub.3 CO              OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         H  OH            OCO.sub.2 CH.sub.3                                                                          (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                          Ph                                                                            isopropyloxy                     OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         H  OH            OMe           (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                          Ph                                                                            isopropyloxy                     OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         H  OH            OC(O)Ph       (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                          Ph                                                                            isopropyloxy                     OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         AcO           Ph         Ph                    OH            F  H             OCH.sub.2 OP(O)(OH).sub.2                                                                   (CH.sub.3).sub.3 CO                                                                      Ph                                                                 Ph                               OCO.sub.2 CH.sub.2 CH.sub.3                                                                 F  H             OCH.sub.2 OP(O)(OH).sub.2                                                                   (CH.sub.3).sub.3 CO                                                                      Ph                                                                 Ph                               OCH.sub.2 OP(O)(OH).sub.2                                                                   F  H             AcO           Ph         2-furanyl                                                                     isobutenyl                                                                    3-furanyl                                                                     2-thienyl                                                                     2-propenyl                                                                    cyclopropyl                                                                   3-thienyl                                                                     isopropyl             OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         F  H             AcO           Ph         2-furanyl                                                                     isobutenyl                                                                    3-furanyl                                                                     2-thienyl                                                                     2-propenyl                                                                    cyclopropyl                                                                   3-thienyl                                                                     isopropyl             OCH.sub.2 OP(O)(OH).sub.2                                                                   F  H             AcO           (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                                     3-thienyl                                                                     isobutenyl                                                                    3-furanyl                                                                     cyclopropyl                                                                   2-thienyl                                                                     Ph                                                                            2-propenyl            OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         F  H             AcO           (CH.sub.3).sub.3 CO                                                                      2-furanyl                                                                     3-thienyl                                                                     isobutenyl                                                                    3-furanyl                                                                     cyclopropyl                                                                   2-thienyl                                                                     Ph                                                                            2-propenyl            OCH.sub.2 OP(O)(OH).sub.2                                                                   F  H             OCO.sub.2 CH.sub.3                                                                          (CH.sub.3).sub.3 CO                                                                      2-furanyl             OCH.sub.2 OP(O)(OH).sub.2                                                                   F  H             OMe           (CH.sub.3).sub.3 CO                                                                      2-furanyl             OCH.sub.2 OP(O)(OH).sub.2                                                                   F  H             OC(O)Ph       (CH.sub.3).sub.3 CO                                                                      2-furanyl             OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         F  H             OCO.sub.2 CH.sub.3                                                                          (CH.sub.3).sub.3 CO                                                                      2-furanyl             OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         F  H             OMe           (CH.sub.3).sub.3 CO                                                                      2-furanyl             OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         F  H             OC(O)Ph       (CH.sub.3).sub.3 CO                                                                      2-furanyl             OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         H  OH            OH            (CH.sub.3).sub.3 CO                                                                      Ph                    OH            H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OH            (CH.sub.3).sub.3 CO                                                                      Ph                    OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OH            (CH.sub.3).sub.3 CO                                                                      Ph                    OH            H  OH            OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         (CH.sub.3).sub.3 CO                                                                      Ph                    OCO.sub.2 CH.sub.2 CH.sub.3                                                                 H  OH            OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         (CH.sub.3).sub.3 CO                                                                      Ph                    OH            F  H             OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         (CH.sub.3).sub.3 CO                                                                      Ph                                                                            2-furanyl                                                                     3-furanyl                                                                     2-thienyl                                                                     3-thienyl                                                                     isobutenyl                                                                    cyclopropyl                                                                   2-propenyl            OCO.sub.2 CH.sub.2 CH.sub.3                                                                 F  H             OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         (CH.sub.3).sub.3 CO                                                                      Ph                                                                            2-furanyl                                                                     3-furanyl                                                                     2-thienyl                                                                     3-thienyl                                                                     isobutenyl                                                                    cyclopropyl                                                                   2-propenyl            OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OAc           Ph         Ph                                                                            2-furanyl             OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OAc           tBuO       Ph                                                                            2-furanyl             OCH.sub.2 (OCH.sub.2).sub.2 OP(O)(OH).sub.2                                                 H  OH            OAc           Ph         Ph                                     OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                           OCH.sub.2 OP(O)(OH).sub.2                                                     OCH.sub.2 (OCH.sub.2).sub.2 OP(O)(OH).sub.2                  OCH.sub.2 (OCH.sub.2).sub.2 OP(O)(OH).sub.2                                                 H  OH            OAc           tBuO       Ph                                                                            2-furanyl             OCH.sub.2 (OCH.sub.2).sub.2 OP(O)(OH).sub.2                                                 H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OAc           tBuO       Ph                                                                            2-furanyl             OCH.sub.2 (OCH.sub.2).sub.2 OP(O)(OH).sub.2                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OAc           tBuO       Ph                                                                            2-furanyl             OCH.sub.2 (OCH.sub.2).sub.2 OP(O)(OH).sub.2                                                 H  OCH.sub.2 (OCH.sub.2).sub.2 OP(O)(OH).sub.2                                                 OAc           tBuO       Ph                                                                            2-furanyl             OCH.sub.2 (OCH.sub.2).sub.3 OP(O)(OH).sub.2                                                 H  OH            OAc           Ph         Ph                    OCH.sub.2 (OCH.sub.2).sub.3 OP(O)(OH).sub.2                                                 H  OH            OAc           tBuO       Ph                                                                            2-furanyl             OCH.sub.2 (OCH.sub.2).sub.3 OP(O)(OH).sub.2                                                 H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OAc           Ph         Ph                                                                 tBuO                             OCH.sub.2 (OCH.sub.2).sub.3 OP(O)(OH).sub.2                                                 H  OCH.sub.2 OP(O)(OH).sub.2                                                                   OAc           tBuO       2-furanyl             OCH.sub.2 (OCH.sub.2).sub.3 OP(O)(OH).sub.2                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OAc           Ph         Ph                                                                 tBuO                             OCH.sub.2 (OCH.sub.2).sub.3 OP(O)(OH).sub.2                                                 H  OCH.sub.2 OCH.sub.2 OP(O)(OH).sub.2                                                         OAc           tBuO       2-furanyl             OCH.sub.2 (OCH.sub.2).sub.3 OP(O)(OH).sub.2                                                 H  OCH.sub.2 (OCH.sub.2).sub.2 OP(O)(OH).sub.2                                                 OAc           Ph         Ph                                                                 tBuO                             OCH.sub.2 (OCH.sub.2).sub.3 OP(O)(OH).sub.2                                                 H  OCH.sub.2 (OCH.sub.2).sub.2 OP(O)(OH).sub.2                                                 OAc           tBuO       2-furanyl             OCH.sub.2 (OCH.sub.2).sub.3 OP(O)(OH).sub.2                                                 H  OCH.sub.2 (OCH.sub.2).sub.3 OP(O)(OH).sub.2                                                 OAc           Ph         Ph                                                                            2-furanyl             OCH.sub.2 (OCH.sub.2).sub.3 OP(O)(OH).sub.2                                                 H  OCH.sub.2 (OCH.sub.2).sub.3 OP(O)(OH).sub.2                                                 OAc           tBuO       Ph                                                                            2-furanyl             __________________________________________________________________________     *"c" indicates cyclo                                                     

We claim:
 1. A compound having the formula ##STR113## wherein R¹ ishydroxy, --OCH₂ (OCH₂)_(m) OP(O)(OH)₂, --OC(O)R^(x) or --OC(O)OR^(x);R^(2') is hydrogen, and R² is hydrogen, hydroxy, --OCH₂ (OCH₂)_(m)OP(O)(OH)₂, --OC(O)R^(x) or --OC(O)OR^(x) ; R³ is hydrogen, hydroxy,C₁₋₆ alkyloxy, --OC(O)R^(x), --OCH₂ (OCH₂)_(m) OP(O)(OH)₂ or--OC(O)OR^(x) ; one of R⁶ or R⁷ is hydrogen and the other is hydroxy,C₁₋₆ alkanoyloxy, or --OCH₂ (OCH₂)_(m) OP(O)(OH₂); or R⁶ and R⁷ togetherform an oxo group; with the proviso that at least one of R¹, R², R³, R⁶or R⁷ is --OCH₂ (OCH₂)_(m) OP(O)(OH)₂ ; m is zero or an integer one tosix inclusive; R⁴ and R⁵ are independently C₁₋₆ alkyl, C₂₋₆ alkenyl,C₂₋₆ alkynyl, or --Z--R⁶ ; Z is a direct bond, C₁₋₆ alkyl or C₂₋₆alkenyl; R⁶ is aryl, substituted aryl, C₃₋₆ cycloalkyl, or heteroaryl; pis 0 or 1; and R^(x) is C₁₋₆ alkyl optionally substituted with one tosix same or different halogen atoms, C₃₋₆ cycloalkyl, C₂₋₆ alkenyl orhydroxy; or R^(x) is a radical of the formula ##STR114## wherein D is abond or C₁₋₆ alkyl; and R^(a), R^(b) and R^(c) are independentlyhydrogen, amino, C₁₋₆ alkylamino, di-C₁₋₆ alkylamino, halogen, C₁₋₆alkyl, or C₁₋₆ alkoxy.
 2. A compound of claim 1 wherein R^(2') ishydrogen, and R² is --OCH₂ OP(O)(OH)₂ ; or a pharmaceutically acceptablesalt thereof.
 3. A compound of claim 2 wherein R¹ is hydroxy,--OC(O)R^(x) or --OC(O)OR^(x).
 4. A compound of claim 3 wherein R^(x) isC₁₋₆ alkyl.
 5. A compound of claim 3 wherein R³ is hydrogen, hydroxy oracetoxy.
 6. A compound of claim 3 wherein R⁴ (O)_(p) is phenyl ort-butoxy.
 7. A compound of claim 3 wherein R⁵ is phenyl, 2-furyl or2-thienyl.
 8. A compound of claim 1 which is2'-O-(ethoxycarbonyl)-7-O-(phosphonooxymethyl)paclitaxel, or apharmaceutically acceptable salt thereof.
 9. The sodium salt of thecompound of claim
 8. 10. The triethanolamine salt of the compound ofclaim
 8. 11. The triethylamine salt of the compound of claim
 8. 12. Thearginine salt of the compound of claim
 8. 13. The lysine salt of thecompound of claim
 8. 14. The ethanolamine salt of the compound of claim8.
 15. The N-methylglucamine salt of the compound of claim
 8. 16. Acompound of claim 1 which is 7-O-(phosphonooxymethyl)paclitaxel, or apharmaceutically acceptable salt thereof.
 17. The sodium salt of thecompound of claim
 16. 18. A compound of claim 1 which is3'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-furyl)-2'-O-ethyloxycarbonyl-7-O-phosphonooxymethylpaclitaxel,or a pharmaceutically acceptable salt thereof.
 19. The triethanolaminesalt of the compound of claim
 18. 20. A compound of claim 1 which is3'-N-debenzoyl-3'-desphenyl-3'-N-(t-butyloxycarbonyl)-3'-(2-thienyl)-2'-O-ethyloxycarbonyl-7-O-phosphonooxymethylpaclitaxelor a pharmaceutically acceptable salt thereof.
 21. The triethanolaminesalt of the compound of claim
 20. 22. A compound of claim 1 which is2'-O-methoxycarbonyl-7-O-phosphonooxymethylpaclitaxel.
 23. A compound ofclaim 1 which is 2'-O-methylcarbonyl-7-O-phosphonooxymethylpaclitaxel.24. A compound of claim 1 which is2'-O-n-propylcarbonyl-7-O-phosphonooxymethylpaclitaxel.
 25. A compoundof claim 1 wherein R¹ is --OCH₂ OP(O)(OH)₂, or a pharmaceuticallyacceptable salt thereof.
 26. A compound of claim 25 wherein R^(2') ishydrogen, R² is hydrogen, hydroxy or --OC(O)OR^(x), and R^(x) is asdefined as claim
 1. 27. A compound of claim 26 wherein R³ is hydrogen,hydroxy or acetoxy.
 28. A compound of claim 26 wherein R⁴ (O)_(p) isphenyl or t-butoxy.
 29. A compound of claim 26 wherein R⁵ is phenyl. 30.A compound of claim 1 which is 2'-O-(phosphonooxymethyl)paclitaxel, or apharmaceutically acceptable salt thereof.
 31. A compound of claim 1wherein R¹ and R² are both --OCH₂ OP(O)(OH)₂, or a pharmaceuticallyacceptable salt thereof.
 32. A compound of claim 1 which is2',7-O-bis(phosphonooxymethyl)paclitaxel or a pharmaceuticallyacceptable salt thereof.
 33. The sodium salt of the compound of claim32.
 34. A compound of claim 1 wherein R¹ is --OCH₂ OCH₂ OP(O)(OH)₂, or apharmaceutically acceptable salt thereof.
 35. A compound of claim 1which is2'-O-phosphonooxymethoxymethyl-7-O-phosphonooxymethylpaclitaxel.
 36. Acompound of claim 1 which is 2'-O-phosphonooxymethoxymethylpaclitaxel,or a pharmaceutically acceptable salt thereof.
 37. The triethanolaminesalt of the compound of claim
 36. 38. A compound of claim 1 wherein R³is --OCH₂ OP(O)(OH)₂, or a pharmaceutically acceptable salt thereof. 39.A compound of claim 1 which is10-desacetyl-3'-N-desbenzoyl-3'-N-(t-butyloxycarbonyl)-10-O-(phosphonooxymethyl)paclitaxel,or a pharmaceutically acceptable salt thereof.
 40. The triethanolaminesalt of compound of claim
 39. 41. A compound of claim 1 wherein R¹ is--OCH₂ OCH₂ OCH₂ OP(O)(OH)₂.
 42. A compound of claim 41 which is2'-O-[(phosphonooxymethoxy)methoxymethyl]paclitaxel.
 43. A compound ofclaim 41 which is2'-O-[(phosphonooxymethoxy)methoxy]methyl-7-O-phosphonooxmethylypaclitaxel.